In the case where data fails to be allocated the error exit path is
via label 'out' where data is dereferenced in a for-loop. Fix this
by exiting via the label 'out_file' instead to avoid the null pointer
dereference.
Addresses-Coverity: ("Dereference after null check")
Fixes: 50d16d44cc ("drm/i915/selftests: Exercise context switching in parallel")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191009100024.23077-1-colin.king@canonical.com
Assign a separate lockclass to the perma-pinned timelines of the
kernel_context, such that we can use them from within the user timelines
should we ever need to inject GPU operations to fixup faults during
request construction.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008185941.15228-1-chris@chris-wilson.co.uk
Volatile objects are marked as DONTNEED while pinned, therefore once
unpinned the backing store can be discarded. This is limited to kernel
internal objects.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: CQ Tang <cq.tang@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008160116.18379-4-matthew.auld@intel.com
Some kernel internal objects may need to be allocated as a contiguous
block, also thinking ahead the various kernel io_mapping interfaces seem
to expect it, although this is purely a limitation in the kernel
API...so perhaps something to be improved.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Michael J Ruhl <michael.j.ruhl@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008160116.18379-3-matthew.auld@intel.com
Support memory regions, as defined by a given (start, end), and allow
creating GEM objects which are backed by said region. The immediate goal
here is to have something to represent our device memory, but later on
we also want to represent every memory domain with a region, so stolen,
shmem, and of course device. At some point we are probably going to want
use a common struct here, such that we are better aligned with say TTM.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008160116.18379-2-matthew.auld@intel.com
A common bane of ours is arbitrary delays in ksoftirqd processing our
submission tasklet. Give the submission tasklet a kick before we wait to
avoid those delays eating into a tight timeout.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008105655.13256-1-chris@chris-wilson.co.uk
At some point in time there was the idea that we could have multiple
stream from the same piece of HW but that never materialized and given
the hard time we already have making everything work with the
submission side, there is no real point having this list of 1 element
around.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008140111.5437-1-chris@chris-wilson.co.uk
Adding DC3CO counter in i915_dmc_info debugfs will be
useful for DC3CO validation.
DMC firmware uses DMC_DEBUG3 register as DC3CO counter
register on TGL, as per B.Specs DMC_DEBUG3 is general
purpose register.
v1: comment modification for DMC_DBUG3.
using GEN >= 12 check instead of IS_TIGERLAKE()
to print DMC_DEBUG3 counter value.
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003081738.22101-7-anshuman.gupta@intel.com
DC3CO is useful power state, when DMC detects PSR2 idle frame
while an active video playback, playing 30fps video on 60hz panel
is the classic example of this use case.
B.Specs:49196 has a restriction to enable DC3CO only for Video Playback.
It will be worthy to enable DC3CO after completion of each pageflip
and switch back to DC5 when display is idle because driver doesn't
differentiate between video playback and a normal pageflip.
We will use Frontbuffer flush call tgl_dc3co_flush() to enable DC3CO
state only for ORIGIN_FLIP flush call, because DC3CO state has primarily
targeted for VPB use case. We are not interested here for frontbuffer
invalidates calls because that triggers PSR2 exit, which will
explicitly disable DC3CO.
DC5 and DC6 saves more power, but can't be entered during video
playback because there are not enough idle frames in a row to meet
most PSR2 panel deep sleep entry requirement typically 4 frames.
As PSR2 existing implementation is using minimum 6 idle frames for
deep sleep, it is safer to enable DC5/6 after 6 idle frames
(By scheduling a delayed work of 6 idle frames, once DC3CO has been
enabled after a pageflip).
After manually waiting for 6 idle frames DC5/6 will be enabled and
PSR2 deep sleep idle frames will be restored to 6 idle frames, at this
point DMC will triggers DC5/6 once PSR2 enters to deep sleep after
6 idle frames.
In future when we will enable S/W PSR2 tracking, we can change the
PSR2 required deep sleep idle frames to 1 so DMC can trigger the
DC5/6 immediately after S/W manual waiting of 6 idle frames get
complete.
v2: calculated s/w state to switch over dc3co when there is an
update. [Imre]
Used cancel_delayed_work_sync() in order to avoid any race
with already scheduled delayed work. [Imre]
v3: Cancel_delayed_work_sync() may blocked the commit work.
hence dropping it, dc5_idle_thread() checks the valid wakeref before
putting the reference count, which avoids any chances of dropping
a zero wakeref. [Imre (IRC)]
v4: Used frontbuffer flush mechanism. [Imre]
v5: Used psr.pipe to extract frontbuffer busy bits. [Imre]
Used cancel_delayed_work_sync() in encoder disable path. [Imre]
Used mod_delayed_work() instead of cancelling and scheduling a
delayed work. [Imre]
Used psr.lock in tgl_dc5_idle_thread() to enable psr2 deep
sleep. [Imre]
Removed DC5_REQ_IDLE_FRAMES macro. [Imre]
v6: Used dc3co_exitline check instead of TGL and dc3co allowed_dc_mask
checks, used delayed_work_pending with the psr lock and removed the
psr2_deep_slp_disabled flag. [Imre]
v7: Code refactoring, moved most of functional code to inte_psr.c [Imre]
Using frontbuffer_bits on psr.pipe check instead of
busy_frontbuffer_bits. [Imre]
Calculating dc3co_exit_delay in intel_psr_enable_locked. [Imre]
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003081738.22101-6-anshuman.gupta@intel.com
DC3CO enabling B.Specs sequence requires to enable end configure
exit scanlines to TRANS_EXITLINE register, programming this register
has to be part of modeset sequence as this can't be change when
transcoder or port is enabled.
When system boots with only eDP panel there may not be real
modeset as BIOS has already programmed the necessary registers,
therefore it needs to force a modeset to enable and configure
DC3CO exitline.
v1: Computing dc3co_exitline crtc state from a DP encoder
compute config. [Imre]
Enabling and disabling DC3CO PSR2 transcoder exitline from
encoder pre_enable and post_disable hooks. [Imre]
Computing dc3co_exitline instead of has_dc3co_exitline bool. [Imre]
v2: Code refactoring for symmetry and to avoid exported function. [Imre]
Removing IS_TIGERLAKE check from compute_config, adding PIPE_A
restriction and clearing dc3co_exitline state if crtc is not active
or it is not PSR2 capable in dc3co exitline compute_config. [Imre]
Using GEN >= 12 check in dc3co exitline get_config. [Imre]
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003081738.22101-5-anshuman.gupta@intel.com
Add target_dc_state and used by set_target_dc_state API
in order to enable DC3CO state with existing DC states.
target_dc_state will enable/disable the desired DC state in
DC_STATE_EN reg when "DC Off" power well gets disable/enable.
v2: commit log improvement.
v3: Used intel_wait_for_register to wait for DC3CO exit. [Imre]
Used gen9_set_dc_state() to allow/disallow DC3CO. [Imre]
Moved transcoder psr2 exit line enablement from tgl_allow_dc3co()
to a appropriate place haswell_crtc_enable(). [Imre]
Changed the DC3CO power well enabled call back logic as
recommended in review comments. [Imre]
v4: Used wait_for_us() instead of intel_wait_for_reg(). [Imre (IRC)]
v5: using udelay() instead of waiting for DC3CO exit status.
v6: Fixed minor unwanted change.
v7: Removed DC3CO powerwell and POWER_DOMAIN_VIDEO.
v8: Uniform checks by using only target_dc_state instead of allowed_dc_mask
in "DC off" power well callback. [Imre]
Adding "DC off" power well id to older platforms. [Imre]
Removed psr2_deep_sleep flag from tgl_set_target_dc_state. [Imre]
v9: Used switch case for target DC state in
gen9_dc_off_power_well_disable(), checking DC3CO state against
allowed DC mask, using WARN_ON() in
tgl_set_target_dc_state(). [Imre]
v10: Code refactoring and using sanitize_target_dc_state(). [Imre]
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003081738.22101-4-anshuman.gupta@intel.com
Enable dc3co state in enable_dc module param and add dc3co
enable mask to allowed_dc_mask and gen9_dc_mask.
v1: Adding enable_dc=3,4 options to enable DC3CO with DC5 and DC6
independently. [Animesh]
v2: Using a switch statement for cleaner code. [Animesh]
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003081738.22101-3-anshuman.gupta@intel.com
Adding following definition to i915_reg.h
1. DC_STATE_EN register DC3CO bit fields and masks.
DC3CO enable bit will be used by driver to make DC3CO
ready for DMC f/w and status bit will be used as DC3CO
entry status.
2. Transcoder EXITLINE register and its bit fields and mask.
Transcoder EXITLINE enable bit represents PSR2 idle frame
reset should be applied at exit line and exitlines mask
represent required number of scanlines at which DC3CO
exit happens.
B.Specs:49196
v1: Use of REG_BIT and using extra space for EXITLINE_ macro
definition. [Animesh]
v2: Grouping EXITLINE reg bits with EXITLINE(trans) define,
no functional change. [Ville]
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191007094607.2111-1-anshuman.gupta@intel.com
If we cannot claim the timeline->mutex while preparing for a wait on it,
we have to skip the timeline. In doing so, treat it as active so that
under a intel_gt_wait_for_idle() loop, we repeat the wait after
scheduling away.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191006165002.30312-4-chris@chris-wilson.co.uk
Avoid going to the base i915 device when we already have a path from gt
to the runtime powermanagement interface. The benefit is that it looks a
bit more self-consistent to always be acquiring the gt->uncore->rpm for
use with the gt->uncore.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191007154531.1750-1-chris@chris-wilson.co.uk
Don't populate the array hw_engine_mask on the stack but instead make it
static. Makes the object code smaller by 316 bytes.
Before:
text data bss dec hex filename
34004 4388 320 38712 9738 gpu/drm/i915/gt/intel_reset.o
After:
text data bss dec hex filename
33528 4548 320 38396 95fc gpu/drm/i915/gt/intel_reset.o
(gcc version 9.2.1, amd64)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191007154151.23245-1-colin.king@canonical.com
The latest documented version of the VBT is 229, but no further data has
been added to the child device definition in block 2. Update the child
device version test to eliminate the "Expected child device config size
for VBT version XXX not known; assuming 39" debug messages from the
logs.
Bspec: 20124
Bspec: 20157
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191002192258.1013-1-matthew.d.roper@intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Lost in the rebasing was Tvrtko's reminder that we need to keep an
uninterruptible wait around for the Ironlake VT-d w/a
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191006165002.30312-3-chris@chris-wilson.co.uk
Pair the gmbus setup and teardown in the same layer. This also fixes the
double gmbus teardown on the i915_driver_modeset_probe() error path.
Move the gmbus setup a bit later in the sequence to make the follow-up
refactoring easier, and to pinpoint any unexpected consequences of this
change right here, instead of the later refactoring.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004122019.12009-3-jani.nikula@intel.com
Split out code related to vga switcheroo register/unregister and state
handling from i915_drv.c into new i915_switcheroo.[ch] files.
It's a bit difficult to draw the line how much to move to the new file
from i915_drv.c, but it seemed to me keeping i915_suspend_switcheroo()
and i915_resume_switcheroo() in place was the cleanest.
No functional changes.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004122019.12009-2-jani.nikula@intel.com
Rename the function per Ville's suggestion. No functional changes.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004122019.12009-1-jani.nikula@intel.com
Our other backends return an actual error value upon failure. Do the
same for stolen objects, which currently just return NULL on failure.
Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004170452.15410-2-matthew.auld@intel.com
The current "disable C3+" workaround for the delayed vblank
irqs on i945gm no longer works. I'm not sure what changed, but
now I need to also disable C2. I also got my hands on a i915gm
machine that suffers from the same issue.
After some furious poking of registers I managed to find a
better workaround: The "Do not Turn off Core Render Clock in C
states" bit. With that I no longer have to disable any C-states,
and as a nice bonus the power cost is only ~1/4 of the
"disable C3+" method (which mind you doesn't even work anymore,
and so would have an even higher power cost if we made it work
by also disabling C2).
So let's throw out all the cpuidle/qos crap and just toggle
the magic bit as needed. And we extend the workaround to cover
i915gm as well.
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003140231.24408-1-ville.syrjala@linux.intel.com
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Keep track of the GEM contexts underneath i915->gem.contexts and assign
them their own lock for the purposes of list management.
v2: Focus on lock tracking; ctx->vm is protected by ctx->mutex
v3: Correct split with removal of logical HW ID
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-15-chris@chris-wilson.co.uk
With the introduction of ctx->engines[] we allow multiple logical
contexts to be used on the same engine (e.g. with virtual engines).
According to bspec, aach logical context requires a unique tag in order
for context-switching to occur correctly between them. [Simple
experiments show that it is not so easy to trick the HW into performing
a lite-restore with matching logical IDs, though my memory from early
Broadwell experiments do suggest that it should be generating
lite-restores.]
We only need to keep a unique tag for the active lifetime of the
context, and for as long as we need to identify that context. The HW
uses the tag to determine if it should use a lite-restore (why not the
LRCA?) and passes the tag back for various status identifies. The only
status we need to track is for OA, so when using perf, we assign the
specific context a unique tag.
v2: Calculate required number of tags to fill ELSP.
Fixes: 976b55f0e1 ("drm/i915: Allow a context to define its set of engines")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111895
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-14-chris@chris-wilson.co.uk
As our global unpark/park keep track of the number of active users, we
can simply move the accounting from the GEM layer to the base GT layer.
It was placed originally inside GEM to benefit from the 100ms extra
delay on idleness, but that has been eliminated and now there is no
substantive difference between the layers. In moving it, we move another
piece of the puzzle out from underneath struct_mutex.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-13-chris@chris-wilson.co.uk
Now that we can retire without taking struct_mutex, we can do so to
handle shrinking the mmap-offset space after an allocation failure.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-11-chris@chris-wilson.co.uk
wait_for_timelines is essentially the same loop as retiring requests
(with an extra timeout), so merge the two into one routine.
v2: i915_retire_requests_timeout and keep VT'd w/a as !interruptible
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-10-chris@chris-wilson.co.uk
We don't need to hold struct_mutex now for retiring requests, so drop it
from i915_retire_requests() and i915_gem_wait_for_idle(), finally
removing I915_WAIT_LOCKED for good.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-8-chris@chris-wilson.co.uk
Now that we now longer need to guarantee that the active callback is
under the struct_mutex, we can lift it out of the i915_gem_park() and
into the engine parking itself.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-7-chris@chris-wilson.co.uk
Forgo the struct_mutex serialisation for i915_active, and interpose its
own mutex handling for active/retire.
This is a multi-layered sleight-of-hand. First, we had to ensure that no
active/retire callbacks accidentally inverted the mutex ordering rules,
nor assumed that they were themselves serialised by struct_mutex. More
challenging though, is the rule over updating elements of the active
rbtree. Instead of the whole i915_active now being serialised by
struct_mutex, allocations/rotations of the tree are serialised by the
i915_active.mutex and individual nodes are serialised by the caller
using the i915_timeline.mutex (we need to use nested spinlocks to
interact with the dma_fence callback lists).
The pain point here is that instead of a single mutex around execbuf, we
now have to take a mutex for active tracker (one for each vma, context,
etc) and a couple of spinlocks for each fence update. The improvement in
fine grained locking allowing for multiple concurrent clients
(eventually!) should be worth it in typical loads.
v2: Add some comments that barely elucidate anything :(
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-6-chris@chris-wilson.co.uk
