Commit Graph

38 Commits

Author SHA1 Message Date
Lyude Paul
8578336985 drm/dp_mst: Remove lies in {up, down}_rep_recv documentation
These are most certainly accessed from far more than the mgr work. In
fact, up_req_recv is -only- ever accessed from outside the mgr work.

Cc: Juston Li <juston.li@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <hwentlan@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20190903204645.25487-19-lyude@redhat.com
2019-09-25 16:35:42 -04:00
Lyude Paul
2f015ec6ea drm/dp_mst: Add sideband down request tracing + selftests
Unfortunately the DP MST helpers do not have much in the way of
debugging utilities. So, let's add some!

This adds basic debugging output for down sideband requests that we send
from the driver, so that we can actually discern what's happening when
sideband requests timeout.

Since there wasn't really a good way of testing that any of this worked,
I ended up writing simple selftests that lightly test sideband message
encoding and decoding as well. Enjoy!

Changes since v1:
* Clean up DO_TEST() and sideband_msg_req_encode_decode() - danvet
* Get rid of pr_fmt(), just define a prefix string instead and use
  drm_printf()
* Check highest bit of VCPI in drm_dp_decode_sideband_req() - danvet
* Make the switch case order between drm_dp_decode_sideband_req() and
  drm_dp_encode_sideband_req() the same - danvet
* Only check DRM_UT_DP - danvet
* Clean up sideband_msg_req_equal() from selftests a bit, and add
  comments explaining why we can't just use memcmp - danvet

Cc: Juston Li <juston.li@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <hwentlan@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190903204645.25487-8-lyude@redhat.com
2019-09-03 19:30:06 -04:00
Sean Paul
268de6530a drm: mst: Fix query_payload ack reply struct
Spec says[1] Allocated_PBN is 16 bits

[1]- DisplayPort 1.2 Spec, Section 2.11.9.8, Table 2-98

Fixes: ad7f8a1f9c ("drm/helper: add Displayport multi-stream helper (v0.6)")
Cc: Lyude Paul <lyude@redhat.com>
Cc: Todd Previte <tprevite@gmail.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190829165223.129662-1-sean@poorly.run
2019-08-29 13:52:46 -04:00
Ville Syrjälä
562836a269 drm/dp_mst: Enable registration of AUX devices for MST ports
All available downstream ports - physical and logical - are exposed for
each MST device. They are listed in /dev/, following the same naming
scheme as SST devices by appending an incremental ID.

Although all downstream ports are exposed, only some will work as
expected. Consider the following topology:

               +---------+
               |  ASIC   |
               +---------+
              Conn-0|
                    |
               +----v----+
          +----| MST HUB |----+
          |    +---------+    |
          |                   |
          |Port-1       Port-2|
    +-----v-----+       +-----v-----+
    |  MST      |       |  SST      |
    |  Display  |       |  Display  |
    +-----------+       +-----------+
          |Port-1
          x

 MST Path  | MST Device
 ----------+----------------------------------
 sst:0     | MST Hub
 mst:0-1   | MST Display
 mst:0-1-1 | MST Display's disconnected DP out
 mst:0-1-8 | MST Display's internal sink
 mst:0-2   | SST Display

On certain MST displays, the upstream physical port will ACK DPCD reads.
However, reads on the local logical port to the internal sink will
*NAK*. i.e. reading mst:0-1 ACKs, but mst:0-1-8 NAKs.

There may also be duplicates. Some displays will return the same GUID
when reading DPCD from both mst:0-1 and mst:0-1-8.

There are some device-dependent behavior as well. The MST hub used
during testing will actually *ACK* read requests on a disconnected
physical port, whereas the MST displays will NAK.

In light of these discrepancies, it's simpler to expose all downstream
ports - both physical and logical - and let the user decide what to use.

v3 changes:
* Change WARN_ON_ONCE -> DRM_ERROR on dpcd read errors
* Docstring and cosmetic fixes

v2 changes:

Moved remote aux device (un)registration to new mst connector late
register and early unregister helpers. Drivers should call these from
their own mst connector function hooks.

This is to solve an issue during driver unload, where mst connector
devices are unregistered before the remote aux devices are. In a setup
where aux devices are created as children of connector devices, the aux
device would be removed too early, and uncleanly. Doing so in
early_unregister solves this issue, as that is called before connector
unregistration.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190723232808.28128-3-sunpeng.li@amd.com
2019-07-25 16:39:35 -04:00
Dave Airlie
c06de56121 Linux 5.0-rc7
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Merge v5.0-rc7 into drm-next

Backmerging for nouveau and imx that needed some fixes for next pulls.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2019-02-18 13:27:15 +10:00
Lyude Paul
eceae14724 drm/dp_mst: Start tracking per-port VCPI allocations
There has been a TODO waiting for quite a long time in
drm_dp_mst_topology.c:

	/* We cannot rely on port->vcpi.num_slots to update
	 * topology_state->avail_slots as the port may not exist if the parent
	 * branch device was unplugged. This should be fixed by tracking
	 * per-port slot allocation in drm_dp_mst_topology_state instead of
	 * depending on the caller to tell us how many slots to release.
	 */

That's not the only reason we should fix this: forcing the driver to
track the VCPI allocations throughout a state's atomic check is
error prone, because it means that extra care has to be taken with the
order that drm_dp_atomic_find_vcpi_slots() and
drm_dp_atomic_release_vcpi_slots() are called in in order to ensure
idempotency. Currently the only driver actually using these helpers,
i915, doesn't even do this correctly: multiple ->best_encoder() checks
with i915's current implementation would not be idempotent and would
over-allocate VCPI slots, something I learned trying to implement
fallback retraining in MST.

So: simplify this whole mess, and teach drm_dp_atomic_find_vcpi_slots()
and drm_dp_atomic_release_vcpi_slots() to track the VCPI allocations for
each port. This allows us to ensure idempotency without having to rely
on the driver as much. Additionally: the driver doesn't need to do any
kind of VCPI slot tracking anymore if it doesn't need it for it's own
internal state.

Additionally; this adds a new drm_dp_mst_atomic_check() helper which
must be used by atomic drivers to perform validity checks for the new
VCPI allocations incurred by a state.

Also: update the documentation and make it more obvious that these
/must/ be called by /all/ atomic drivers supporting MST.

Changes since v9:
* Add some missing changes that were requested by danvet that I forgot
  about after I redid all of the kref stuff:
  * Remove unnecessary state changes in intel_dp_mst_atomic_check
  * Cleanup atomic check logic for VCPI allocations - all we need to check in
    compute_config is whether or not this state disables a CRTC, then free
    VCPI based off that

Changes since v8:
 * Fix compile errors, whoops!

Changes since v7:
 - Don't check for mixed stale/valid VCPI allocations, just rely on
 connector registration to stop such erroneous modesets

Changes since v6:
 - Keep a kref to all of the ports we have allocations on. This required
   a good bit of changing to when we call drm_dp_find_vcpi_slots(),
   mainly that we need to ensure that we only redo VCPI allocations on
   actual mode or CRTC changes, not crtc_state->active changes.
   Additionally, we no longer take the registration of the DRM connector
   for each port into account because so long as we have a kref to the
   port in the new or previous atomic state, the connector will stay
   registered.
 - Use the small changes to drm_dp_put_port() to add even more error
   checking to make misusage of the helpers more obvious. I added this
   after having to chase down various use-after-free conditions that
   started popping up from the new helpers so no one else has to
   troubleshoot that.
 - Move some accidental DRM_DEBUG_KMS() calls to DRM_DEBUG_ATOMIC()
 - Update documentation again, note that find/release() should both not be
   called on the same port in a single atomic check phase (but multiple
   calls to one or the other is OK)

Changes since v4:
 - Don't skip the atomic checks for VCPI allocations if no new VCPI
   allocations happen in a state. This makes the next change I'm about
   to list here a lot easier to implement.
 - Don't ignore VCPI allocations on destroyed ports, instead ensure that
   when ports are destroyed and still have VCPI allocations in the
   topology state, the only state changes allowed are releasing said
   ports' VCPI. This prevents a state with a mix of VCPI allocations
   from destroyed ports, and allocations from valid ports.

Changes since v3:
 - Don't release VCPI allocations in the topology state immediately in
   drm_dp_atomic_release_vcpi_slots(), instead mark them as 0 and skip
   over them in drm_dp_mst_duplicate_state(). This makes it so
   drm_dp_atomic_release_vcpi_slots() is still idempotent while also
   throwing warnings if the driver messes up it's book keeping and tries
   to release VCPI slots on a port that doesn't have any pre-existing
   VCPI allocation - danvet
 - Change mst_state/state in some debugging messages to "mst state"

Changes since v2:
 - Use kmemdup() for duplicating MST state - danvet
 - Move port validation out of duplicate state callback - danvet
 - Handle looping through MST topology states in
   drm_dp_mst_atomic_check() so the driver doesn't have to do it
 - Fix documentation in drm_dp_atomic_find_vcpi_slots()
 - Move the atomic check for each individual topology state into it's
   own function, reduces indenting
 - Don't consider "stale" MST ports when calculating the bandwidth
   requirements. This is needed because originally we relied on the
   state duplication functions to prune any stale ports from the new
   state, which would prevent us from incorrectly considering their
   bandwidth requirements alongside legitimate new payloads.
 - Add function references in drm_dp_atomic_release_vcpi_slots() - danvet
 - Annotate atomic VCPI and atomic check functions with __must_check
   - danvet

Changes since v1:
 - Don't use the now-removed ->atomic_check() for private objects hook,
   just give drivers a function to call themselves

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-19-lyude@redhat.com
2019-01-10 20:42:13 -05:00
Lyude Paul
bea5c38f1e drm/dp_mst: Add some atomic state iterator macros
Changes since v6:
 - Move EXPORT_SYMBOL() for drm_dp_mst_topology_state_funcs to this
   commit
 - Document __drm_dp_mst_state_iter_get() and note that it shouldn't be
   called directly

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-18-lyude@redhat.com
2019-01-10 20:38:38 -05:00
Lyude Paul
ebcc0e6b50 drm/dp_mst: Introduce new refcounting scheme for mstbs and ports
The current way of handling refcounting in the DP MST helpers is really
confusing and probably just plain wrong because it's been hacked up many
times over the years without anyone actually going over the code and
seeing if things could be simplified.

To the best of my understanding, the current scheme works like this:
drm_dp_mst_port and drm_dp_mst_branch both have a single refcount. When
this refcount hits 0 for either of the two, they're removed from the
topology state, but not immediately freed. Both ports and branch devices
will reinitialize their kref once it's hit 0 before actually destroying
themselves. The intended purpose behind this is so that we can avoid
problems like not being able to free a remote payload that might still
be active, due to us having removed all of the port/branch device
structures in memory, as per:

commit 91a25e4631 ("drm/dp/mst: deallocate payload on port destruction")

Which may have worked, but then it caused use-after-free errors. Being
new to MST at the time, I tried fixing it;

commit 263efde31f ("drm/dp/mst: Get validated port ref in drm_dp_update_payload_part1()")

But, that was broken: both drm_dp_mst_port and drm_dp_mst_branch structs
are validated in almost every DP MST helper function. Simply put, this
means we go through the topology and try to see if the given
drm_dp_mst_branch or drm_dp_mst_port is still attached to something
before trying to use it in order to avoid dereferencing freed memory
(something that has happened a LOT in the past with this library).
Because of this it doesn't actually matter whether or not we keep keep
the ports and branches around in memory as that's not enough, because
any function that validates the branches and ports passed to it will
still reject them anyway since they're no longer in the topology
structure. So, use-after-free errors were fixed but payload deallocation
was completely broken.

Two years later, AMD informed me about this issue and I attempted to
come up with a temporary fix, pending a long-overdue cleanup of this
library:

commit c54c7374ff ("drm/dp_mst: Skip validating ports during destruction, just ref")

But then that introduced use-after-free errors, so I quickly reverted
it:

commit 9765635b30 ("Revert "drm/dp_mst: Skip validating ports during destruction, just ref"")

And in the process, learned that there is just no simple fix for this:
the design is just broken. Unfortunately, the usage of these helpers are
quite broken as well. Some drivers like i915 have been smart enough to
avoid accessing any kind of information from MST port structures, but
others like nouveau have assumed, understandably so, that
drm_dp_mst_port structures are normal and can just be accessed at any
time without worrying about use-after-free errors.

After a lot of discussion, me and Daniel Vetter came up with a better
idea to replace all of this.

To summarize, since this is documented far more indepth in the
documentation this patch introduces, we make it so that drm_dp_mst_port
and drm_dp_mst_branch structures have two different classes of
refcounts: topology_kref, and malloc_kref. topology_kref corresponds to
the lifetime of the given drm_dp_mst_port or drm_dp_mst_branch in it's
given topology. Once it hits zero, any associated connectors are removed
and the branch or port can no longer be validated. malloc_kref
corresponds to the lifetime of the memory allocation for the actual
structure, and will always be non-zero so long as the topology_kref is
non-zero. This gives us a way to allow callers to hold onto port and
branch device structures past their topology lifetime, and dramatically
simplifies the lifetimes of both structures. This also finally fixes the
port deallocation problem, properly.

Additionally: since this now means that we can keep ports and branch
devices allocated in memory for however long we need, we no longer need
a significant amount of the port validation that we currently do.

Additionally, there is one last scenario that this fixes, which couldn't
have been fixed properly beforehand:

- CPU1 unrefs port from topology (refcount 1->0)
- CPU2 refs port in topology(refcount 0->1)

Since we now can guarantee memory safety for ports and branches
as-needed, we also can make our main reference counting functions fix
this problem by using kref_get_unless_zero() internally so that topology
refcounts can only ever reach 0 once.

Changes since v4:
* Change the kernel-figure summary for dp-mst/topology-figure-1.dot a
  bit - danvet
* Remove figure numbers - danvet

Changes since v3:
* Remove rebase detritus - danvet
* Split out purely style changes into separate patches - hwentlan

Changes since v2:
* Fix commit message - checkpatch
* s/)-1/) - 1/g - checkpatch

Changes since v1:
* Remove forward declarations - danvet
* Move "Branch device and port refcounting" section from documentation
  into kernel-doc comments - danvet
* Export internal topology lifetime functions into their own section in
  the kernel-docs - danvet
* s/@/&/g for struct references in kernel-docs - danvet
* Drop the "when they are no longer being used" bits from the kernel
  docs - danvet
* Modify diagrams to show how the DRM driver interacts with the topology
  and payloads - danvet
* Make suggested documentation changes for
  drm_dp_mst_topology_get_mstb() and drm_dp_mst_topology_get_port() -
  danvet
* Better explain the relationship between malloc refs and topology krefs
  in the documentation for drm_dp_mst_topology_get_port() and
  drm_dp_mst_topology_get_mstb() - danvet
* Fix "See also" in drm_dp_mst_topology_get_mstb() - danvet
* Rename drm_dp_mst_topology_get_(port|mstb)() ->
  drm_dp_mst_topology_try_get_(port|mstb)() and
  drm_dp_mst_topology_ref_(port|mstb)() ->
  drm_dp_mst_topology_get_(port|mstb)() - danvet
* s/should/must in docs - danvet
* WARN_ON(refcount == 0) in topology_get_(mstb|port) - danvet
* Move kdocs for mstb/port structs inline - danvet
* Split drm_dp_get_last_connected_port_and_mstb() changes into their own
  commit - danvet

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-7-lyude@redhat.com
2019-01-10 20:12:19 -05:00
Lyude Paul
c235316d93 drm/dp_mst: Add __must_check to drm_dp_mst_topology_mgr_resume()
Since I've had to fix two cases of drivers not checking the return code
from this function, let's make the compiler complain so this doesn't
come up again in the future.

Changes since v1:
* Remove unneeded __must_check in function declaration - danvet

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190108211133.32564-4-lyude@redhat.com
2019-01-08 17:58:27 -05:00
Daniel Vetter
16bff572cc drm/dp-mst-helper: Remove hotplug callback
When everyone implements it exactly the same way, among all 4
implementations, there's not really a need to overwrite this at all.

Aside: drm_kms_helper_hotplug_event is pretty much core functionality
at this point. Probably should move it there.

Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181128221234.15054-1-daniel.vetter@ffwll.ch
2018-12-10 11:01:15 +01:00
Lyude Paul
f676481535 drm/dp_mst: Remove all evil duplicate state pointers
There's no reason to track the atomic state three times. Unfortunately,
this is currently what we're doing, and even worse is that there is only
one actually correct state pointer: the one in mst_state->base.state.
mgr->state never seems to be used, along with the one in
mst_state->state.

This confused me for over 4 hours until I realized there was no magic
behind these pointers. So, let's save everyone else from the trouble.

Signed-off-by: Lyude Paul <lyude@redhat.com>.
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181023231251.16883-3-lyude@redhat.com
2018-10-24 15:44:45 -04:00
Dhinakaran Pandiyan
0bb9c2b27f drm/dp/mst: Sideband message transaction to power up/down nodes
The POWER_DOWN_PHY and POWER_UP_PHY sideband message transactions allow
the source to reqest any node in a mst path or a whole path to be
powered down or up. This allows drivers to target a specific sink in the
MST topology, an improvement over just power managing the imediate
downstream device. Secondly, since the request-reply protocol waits for an
ACK, we can be sure that a downstream sink has enough time to respond to a
power up/down request.

v2: Fix memory leak (Lyude)
Cc: Lyude <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170907001458.9399-1-dhinakaran.pandiyan@intel.com
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
2017-09-11 16:03:57 +03:00
Ville Syrjälä
a4370c7774 drm/atomic: Make private objs proper objects
Make the atomic private object stuff less special by introducing proper
base classes for the object and its state. Drivers can embed these in
their own appropriate objects, after which these things will work
exactly like the plane/crtc/connector states during atomic operations.

v2: Reorder to not depend on drm_dynarray (Daniel)

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> #v1
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170712155102.26276-3-ville.syrjala@linux.intel.com
2017-07-13 19:28:43 +03:00
Pandiyan, Dhinakaran
edb1ed1ab7 drm/dp: Add DP MST helpers to atomically find and release vcpi slots
drm_dp_atomic_find_vcpi_slots() should be called from ->atomic_check() to
check there are sufficient vcpi slots for a mode and to add that to the
state. This should be followed by a call to drm_dp_mst_allocate_vcpi()
in ->atomic_commit() to initialize a struct vcpi for the port.

drm_dp_atomic_release_vcpi_slots() should be called from
->atomic_check() to release a port's vcpi slot allocation from the
state.

Drivers that do not make use of this atomic helper are expected to call
drm_dp_find_vcpi_slots() instead before calling
drm_dp_mst_allocate_vcpi().

v3: drm_dp_atomic_release_vcpi_slots() now needs to know how many slots
    to release as we may not have a valid reference to port.
v2:
Added checks for verifying the port reference is valid
Moved get_mst_topology_state() into the helpers (Daniel)
Changed find_vcpi_slots() to not depend on current allocation

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Harry Wentland <Harry.wentland@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1492753893-3748-4-git-send-email-dhinakaran.pandiyan@intel.com
2017-05-04 15:02:47 +02:00
Pandiyan, Dhinakaran
3f3353b7e1 drm/dp: Introduce MST topology state to track available link bandwidth
Link bandwidth is shared between multiple display streams in DP MST
configurations. The DP MST topology manager structure maintains the
shared link bandwidth for a primary link directly connected to the GPU. For
atomic modesetting drivers, checking if there is sufficient link bandwidth
for a mode needs to be done during the atomic_check phase to avoid failed
modesets. Let's encapsulate the available link bw information in a
private state structure so that bw can be allocated and released atomically
for each of the ports sharing the primary link.

v3: WARN_ON() if connection_mutex is not held (Archit)
v2: Included kernel doc, moved state initialization and switched to
kmemdup() for allocation (Daniel)

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Harry Wentland <Harry.wentland@amd.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1492753893-3748-3-git-send-email-dhinakaran.pandiyan@intel.com
2017-05-04 15:02:46 +02:00
Pandiyan, Dhinakaran
1e797f556c drm/dp: Split drm_dp_mst_allocate_vcpi
drm_dp_mst_allocate_vcpi() apart from setting up the vcpi structure,
also finds if there are enough slots available. This check is a duplicate
of that implemented in drm_dp_mst_find_vcpi_slots(). Let's move this check
out and reuse the existing drm_dp_mst_find_vcpi_slots() function to check
if there are enough vcpi slots before allocating them.

This brings the check to one place. Additionally drivers that will use MST
state tracking for atomic modesets can use the atomic version of
find_vcpi_slots() and reuse drm_dp_mst_allocate_vcpi()

Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1489648231-30700-4-git-send-email-dhinakaran.pandiyan@intel.com
2017-03-22 21:47:44 +01:00
Pandiyan, Dhinakaran
feb2c3bc33 drm/dp: Kill unused MST vcpi slot availability tracking
The avail_slots member in the MST topology manager is never updated to
reflect the available vcpi slots. The check is effectively against
total slots, 63. So, let's make that check obvious and remove
avail_slots. While at it, make debug messages more descriptive.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Harry Wentland <Harry.wentland@amd.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1489648231-30700-3-git-send-email-dhinakaran.pandiyan@intel.com
2017-03-22 21:46:41 +01:00
Pandiyan, Dhinakaran
a538d6137d drm/dp: Kill total_pbn and total_slots in struct drm_dp_mst_topology_mgr
The total vcpi time slots is always 63 and does not depend on the link BW,
remove total_slots from MST topology manager struct. The next change is to
remove total_pbn which is hardcoded to 2560. The total PBN that the
topology manager allocates from depends on the link rate and is not a
constant. So, fix this by removing the total_pbn member itself.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Harry Wentland <Harry.wentland@amd.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1489648231-30700-2-git-send-email-dhinakaran.pandiyan@intel.com
2017-03-22 21:46:21 +01:00
Daniel Vetter
6806cdf9aa drm/kms-helpers: Use recommened kerneldoc for struct member refs
I just learned that &struct_name.member_name works and looks pretty
even. It doesn't (yet) link to the member directly though, which would
be really good for big structures or vfunc tables (where the
per-member kerneldoc tends to be long).

Also some minor drive-by polish where it makes sense, I read a lot
of docs ...

v2: Comments from Gustavo.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Rewiewed-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170125062657.19270-2-daniel.vetter@ffwll.ch
2017-01-25 16:18:57 +01:00
Dhinakaran Pandiyan
7b0a89a6db drm/dp: Store drm_device in MST topology manager
struct drm_dp_mst_topology_mgr currently stores a pointer to struct dev.
Changing this to instead hold a pointer to drm_device is more useful as it
gives access to DRM structures. This also makes it consistent with other
DRM structures like drm_crtc, drm_connector etc.

Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1485301777-3465-2-git-send-email-dhinakaran.pandiyan@intel.com
2017-01-25 06:01:48 +01:00
Daniel Vetter
132d49d728 drm/dp-mst: Missing kernel doc
Cc: Dave Airlie <airlied@redhat.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1468612088-9721-7-git-send-email-daniel.vetter@ffwll.ch
2016-07-19 10:31:53 +02:00
Daniel Vetter
cb021a3eb6 drm/dp-mst: Remove tx_down_in_progress
Just replicates whether the list is empty or not. Nuke code
to avoid writing docs for it!

Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1468612088-9721-6-git-send-email-daniel.vetter@ffwll.ch
2016-07-19 10:31:40 +02:00
Hersen Wu
5e93b8208d drm/dp/mst: move GUID storage from mgr, port to only mst branch
Previous implementation does not handle case below: boot up one MST branch
to DP connector of ASIC. After boot up, hot plug 2nd MST branch to DP output
of 1st MST, GUID is not created for 2nd MST branch. When downstream port of
2nd MST branch send upstream request, it fails because 2nd MST branch GUID
is not available.

New Implementation: only create GUID for MST branch and save it within Branch.

Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Cc: stable@vger.kernel.org
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2016-02-05 15:23:49 +10:00
Dave Airlie
28f03607bb Merge tag 'topic/drm-misc-2016-01-17' of git://anongit.freedesktop.org/drm-intel into drm-next
Since your main drm-next pull isn't out of the door yet I figured I might
as well flush out drm-misc instead of delaying for 4.6. It's really just
random stuff all over, biggest thing probably connector_mask tracking from
Maarten.

* tag 'topic/drm-misc-2016-01-17' of git://anongit.freedesktop.org/drm-intel: (24 commits)
  drm/fb_cma_helper: Remove implicit call to disable_unused_functions
  drm/sysfs: use kobj_to_dev()
  drm/i915: Init power domains early in driver load
  drm: Do not set connector->encoder in drivers
  apple-gmux: Add initial documentation
  drm: move MODULE_PARM_DESC to other file
  drm/edid: index CEA/HDMI mode tables using the VIC
  drm/atomic: Remove drm_atomic_connectors_for_crtc.
  drm/i915: Update connector_mask during readout, v2.
  drm: Remove opencoded drm_gem_object_release_handle()
  drm: Do not set outparam on error during GEM handle allocation
  drm/docs: more leftovers from the big vtable documentation pile
  drm/atomic-helper: Reject legacy flips on a disabled pipe
  drm/atomic: add connector mask to drm_crtc_state.
  drm/tegra: Use __drm_atomic_helper_reset_connector for subclassing connector state, v2.
  drm/atomic: Add __drm_atomic_helper_connector_reset, v2.
  drm/i915: Set connector_state->connector using the helper.
  drm: Use a normal idr allocation for the obj->name
  drm: Only bump object-reference count when adding first handle
  drm: Balance error path for GEM handle allocation
  ...
2016-01-18 07:01:16 +10:00
Mykola Lysenko
1f16ee7fa1 drm/dp/mst: always send reply for UP request
We should always send reply for UP request in order
to make downstream device clean-up resources appropriately.

Issue was that reply for UP request was sent only once.

Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Mykola Lysenko <Mykola.Lysenko@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
2016-01-04 12:05:55 -05:00
Julia Lawall
69a0f89c06 drm/dp/mst: constify drm_dp_mst_topology_cbs structures
The drm_dp_mst_topology_cbs structures are never modified, so declare them
as const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2016-01-04 08:09:58 +01:00
Libin Yang
ef8f9bea13 dp/mst: add SDP stream support
This adds code to initialise the SDP streams
for a sink in the simplest ordering.

I've no idea how you'd want to control the
ordering at this level, so don't bother
until someone comes up with a use case.

Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Libin Yang <libin.yang@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449036584-105393-1-git-send-email-libin.yang@linux.intel.com
2015-12-10 10:00:42 +01:00
Dave Airlie
ae491542cb drm/dp/mst: make mst i2c transfer code more robust.
This zeroes the msg so no random stack data ends up getting
sent, it also limits the function to not accepting > 4
i2c msgs.

Cc: stable@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-15 09:06:20 +10:00
Dave Airlie
d9515c5ec1 drm/dp/mst: split connector registration into two parts (v2)
In order to cache the EDID properly for tiled displays, we
need to retrieve it before we register the connector with
userspace, otherwise userspace can call get resources
and try and get the edid before we've even cached it.

This fixes some problems when hotplugging mst monitors,
with X/mutter running. As mutter seems to get 0 modes
for one of the monitors in the tile.

v2: fix warning in radeon
handle tile setting in cached path rather than
get edid path.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02 15:34:41 +10:00
Dave Airlie
6b8eeca65b drm/dp/mst: close deadlock in connector destruction.
I've only seen this once, and I failed to capture the
lockdep backtrace, but I did some investigations.

If we are calling into the MST layer from EDID probing,
we have the mode_config mutex held, if during that EDID
probing, the MST hub goes away, then we can get a deadlock
where the connector destruction function in the driver
tries to retake the mode config mutex.

This offloads connector destruction to a workqueue,
and avoid the subsequenct lock ordering issue.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-06-25 11:57:23 +10:00
Dave Airlie
87f5942d1f drm/dp_mst: add a function to retrieve vcpi slots
radeon requires this to get the slots for later filling
out a table on every transition.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2015-03-19 12:26:45 -04:00
Dave Airlie
c6a0aed4d4 drm/mst: cached EDID for logical ports (v2)
Logical ports are never going to have EDID changes,
they are used for the internal ports on MST monitors.

We cache the EDIDs from these to save time at MST probe.

v2: drop misplace tile property line, meant for other patch.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-12-09 09:56:47 +10:00
Dave Airlie
4fb2ac6ebe drm: Miscellaneous fixes for v3.19-rc1
This is a small collection of fixes that I've been carrying around for a
 while now. Many of these have been posted and reviewed or acked. The few
 that haven't I deemed too trivial to bother.
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Merge tag 'drm/fixes/for-3.19-rc1' of git://people.freedesktop.org/~tagr/linux into drm-next

drm: Miscellaneous fixes for v3.19-rc1

This is a small collection of fixes that I've been carrying around for a
while now. Many of these have been posted and reviewed or acked. The few
that haven't I deemed too trivial to bother.

* tag 'drm/fixes/for-3.19-rc1' of git://people.freedesktop.org/~tagr/linux:
  video/hdmi: Relicense header under MIT license
  drm/gma500: mdfld: Reuse video/mipi_display.h
  drm: Make drm_mode_create_tv_properties() signature consistent
  drm: Implement drm_get_pci_dev() dummy for !PCI
  drm/prime: Use unsigned type for number of pages
  drm/gem: Fix typo in kerneldoc
  drm: Use const data when creating blob properties
  drm: Use size_t for blob property sizes
2014-11-15 09:37:20 +10:00
Thierry Reding
12e6cecd55 drm: Use const data when creating blob properties
Creating a blob property will always copy the input data so the data
that is passed in can be const.

Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-11-13 10:43:49 +01:00
Dave Airlie
1f9e14baa9 Merge tag 'topic/core-stuff-2014-11-05' of git://anongit.freedesktop.org/drm-intel into drm-next
Just various stuff all over from a bunch of people. Shortlog gives a beter
overview, it's really all misc drm patches.

* tag 'topic/core-stuff-2014-11-05' of git://anongit.freedesktop.org/drm-intel:
  drm/edid: add #defines and helpers for ELD
  drm/dp: Add counters in the drm_dp_aux struct for I2C NACKs and DEFERs
  drm: Remove compiler BUG_ON() test
  drm: Fix DRM_FORCE_ON_DIGITAL use
  drm/gma500: Don't destroy DRM properties in the driver
  drm/i915: Don't destroy DRM properties in the driver
  drm: Add a note to drm_property_create() about property lifetime
  gpu: drm: Fix warning caused by a parameter description in drm_crtc.c
  drm/dp-helper: Move the legacy helpers to gma500
  drm/crtc: Remove duplicated ioctl code
  drm/crtc: Fix two typos
  gpu:drm: Fix typo in Documentation/DocBook/drm.xml
  gpu: drm: drm_dp_mst_topology.c: Fix improper use of strncat
  drm: drm_err: Remove unnecessary __func__ argument
  drm: Implement O_NONBLOCK support on /dev/dri/cardN
2014-11-07 10:58:46 +10:00
Masanari Iida
32197aab04 gpu:drm: Fix typo in Documentation/DocBook/drm.xml
This patch fix spelling typos found in drm.xml.
It is because the file is generated from comments in
source codes, I have to fix the typos within source files.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-10-21 10:55:33 +02:00
Dave Airlie
dfda0df342 drm/mst: rework payload table allocation to conform better.
The old code has problems with the Dell MST monitors due to some
assumptions I made that weren't true.

I initially thought the Virtual Channel Payload IDs had to be in
the DPCD table in ascending order, however it appears that assumption
is bogus.

The old code also assumed it was possible to insert a member
into the table and it would move other members up, like it does
when you remove table entries, however reality has shown this
isn't true.

So the new code allocates VCPIs separate from entries in the payload
tracking table, and when we remove an entry from the DPCD table,
I shuffle the tracking payload entries around in the struct.

This appears to make VT switch more robust (still not perfect)
with an MST enabled Dell monitor.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-10-13 14:40:53 +10:00
Dave Airlie
ad7f8a1f9c drm/helper: add Displayport multi-stream helper (v0.6)
This is the initial import of the helper for displayport multistream.

It consists of a topology manager, init/destroy/set mst state

It supports DP 1.2 MST sideband msg protocol handler - via hpd irqs

connector detect and edid retrieval interface.

It supports i2c device over DP 1.2 sideband msg protocol (EDID reads only)

bandwidth manager API via vcpi allocation and payload updating,
along with a helper to check the ACT status.

Objects:
MST topology manager - one per toplevel MST capable GPU port - not sure if this should be higher level again
MST branch unit - one instance per plugged branching unit - one at top of hierarchy - others hanging from ports
MST port - one port per port reported by branching units, can have MST units hanging from them as well.

Changes since initial posting:
a) add a mutex responsbile for the queues, it locks the sideband and msg slots, and msgs to transmit state
b) add worker to handle connection state change events, for MST device chaining and hotplug
c) add a payload spinlock
d) add path sideband msg support
e) fixup enum path resources transmit
f) reduce max dpcd msg to 16, as per DP1.2 spec.
g) separate tx queue kicking from irq processing and move irq acking back to drivers.

Changes since v0.2:
a) reorganise code,
b) drop ACT forcing code
c) add connector naming interface using path property
d) add topology dumper helper
e) proper reference counting and lookup for ports and mstbs.
f) move tx kicking into a workq
g) add aux locking - this should be redone
h) split teardown into two parts
i) start working on documentation on interface.

Changes since v0.3:
a) vc payload locking and tracking fixes
b) add hotplug callback into driver - replaces crazy return 1 scheme
c) txmsg + mst branch device refcount fixes
d) don't bail on mst shutdown if device is gone
e) change irq handler to take all 4 bytes of SINK_COUNT + ESI vectors
f) make DP payload updates timeout longer - observed on docking station redock
g) add more info to debugfs dumper

Changes since v0.4:
a) suspend/resume support
b) more debugging in debugfs

Changes since v0.5:
a) use byte * to avoid unnecessary stack usage
b) fix num_sdp_streams interpretation.
c) init payload state for unplug events
d) remove lenovo dock sink count hack
e) drop aux lock - post rebase
f) call hotplug on port destroy

TODO:
misc features

Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-07-08 11:41:22 +10:00