It happens on occasion that developers of generic user-space applications
abuse the dumb buffer API to get hold of drm buffers that they can both
mmap() and use for GPU acceleration, using the assumptions that dumb buffers
and buffers available for GPU are
a) The same type and can be aribtrarily type-casted.
b) fully coherent.
This patch makes the most widely used drivers warn nicely when that happens,
the next step will be to fail.
v2: Move drmP.h changes to drm_gem.h. Fix Radeon dumb mmap breakage.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
We need the HPLL frequency when calculating cdclk. Currently we read
that out from the hardware every single time, which isn't going to fly
very well if the device is runtime suspended. So cache the HPLL
frequency in dev_priv and use the cached value.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reference: https://bugs.freedesktop.org/show_bug.cgi?id=82939
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
So that it can be used by the flip code to wait for rendering without
holding any locks.
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Implement common forcewake functions shared by Gen9 features.
v2: Make the focewake_{get,put} functions static (Mika)
Small coding style fix in the function definition (Damien)
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Zhe Wang <zhe1.wang@intel.com> (v1)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> (v2)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
To correctly flush the new DDB allocation we need to know about the pipe
allocation layout inside the DDB in order to sequence the re-allocation
to not cause a newly allocated pipe to fetch from a space that was
previously allocated to another pipe.
This patch preserves the per-pipe (start,end) allocation to be used in
the flush.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Ville suggested that we should use the same semantics as C arrays to
reduce the number of those pesky +1/-1 in the allocation code.
This patch leaves the debugfs file as is, showing the internal DDB
allocation structure, not the values written in the registers.
v2: Remove the test on ->end in skl_ddb_entry_size() (Ville)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This patch implements the watermark algorithm and its necessary
functions. Two function pointers skl_update_wm and
skl_update_sprite_wm are provided. The skl_update_wm will update
the watermarks for the crtc provided as an argument and then
checks for change in DDB allocation for other active pipes and
recomputes the watermarks for those Pipes and planes as well.
Finally it does the register programming for all dirty pipes.
The trigger of the Watermark double buffer registers will have
to be once the plane configurations are done by the caller.
v2: fixed the divide-by-0 error in the results computation func.
Also reworked the PLANE_WM register values computation func to
make it more compact. Incorporated all other review comments
from Damien.
v3: Changed the skl_compute_plane_wm function to now return success
or failure. Also the result blocks and lines are computed here
instead of in skl_compute_wm_results function.
v4: Adjust skl_ddb_alloc_changed() to the new planes/cursor split
(Damien)
v5: Reworked the affected functions to implement new plane/cursor
split.
v6: Rework the logic that triggers the DDB allocation and WM computation
of skl_update_other_pipe_wm() to not depend on non-computed DDB
values.
Always give a valid cursor_width (at boot it's 0) to keep the
invariant that we consider the cursor plane always enabled.
Otherwise we end up dividing by 0 in skl_compute_plane_wm()
(Damien Lespiau)
v7: Spell out allocation
skl_ddb_ functions should have the ddb as first argument
Make the skl_ddb_alloc_changed() parameters const
(Damien)
v8: Rebase on top of the crtc->primary changes
v9: Split the staging results structure to not exceed the 1Kb stack
allocation in skl_update_wm()
v10: Make skl_pipe_pixel_rate() take a pointer to the pipe config
Add a comment about overflow considerations for skl_wm_method1()
Various additions of const
Various use of sizeof(variable) instead of sizeof(type)
Various move of variable definitons to a narrower scope
Zero initialize some stack allocated structures to make sure we
don't have garbage in case we don't write all the values
(Ville)
v11: Remove non-necessary default number of blocks/lines when the plane
is disabled (Ville)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Pradeep Bhat <pradeep.bhat@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We now need to allocate space in the DDB for planes being scanned out
ourselves. The data structure to represent an allocation mirrors what
we'll need to write in the registers later on: (start, end).
We add that allocation datat to the skl_wm_values structure as part of
the values to program the hardware with.
v2: Split planes and cursor for consistency.
v3: Make the skl_ddb_entry_size() parameter const
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This patch defines the structures needed for computation of
watermarks of pipes and planes for SKL.
v2: Incorporated Damien's review comments and removed unused fields
in structs for future features like rotation, drrs and scaling.
The skl_wm_values struct is now made more generic across planes
and cursor planes for all pipes.
v3: implemented the plane/cursor split.
v4: Change the wm union back to a structure (Ville, Daniel)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Pradeep Bhat <pradeep.bhat@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This patch reads the memory latency values for all the 8 levels for
SKL. These values are needed for the Watermark computation.
v2: Incorporated the review comments from Damien on register
indentation.
v3: Updated the code to use the sandybridge_pcode_read for reading
memory latencies for GEN9.
v4: Don't put gen 9 in the middle of an ordered list of ifs
(Damien)
v5: take the rps.hw_lock around sandybridge_pcode_read() (Damien)
v6: Use gen >= 9 in the pcode_read() function for data1.
Move the defines near the gen6 ones and prefix them with PCODE.
Remove unused timeout define (the pcode_read() code has a larger
timeout already).
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Pradeep Bhat <pradeep.bhat@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The function was removed in:
commit 037bde19a4
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu Mar 27 08:24:19 2014 +0000
Revert "drm/i915: Disable/Enable PM Intrrupts based on the current freq."
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Chris removed the code using it in:
commit be2d599b5d
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed Sep 10 19:52:18 2014 +0100
drm/i915: Remove dead code, i915_gem_verify_gtt
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
There's no users left after the conversion to calculate clocks before
disabling crtcs during mode set.
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
It is possible for a mode set to fail if there aren't shared DPLLS that
match the new configuration requirement or other errors in clock
computation. If that step is executed after disabling crtcs, in the
failure case the hardware configuration is changed and needs to be
restored. Doing those things early will allow the mode set to fail
before actually touching the hardware.
Follow up patches will convert different platforms to use the new
infrastructure.
v2: Keep pll->new_config valid only during mode set (Ville)
Use kmemdup() in i915_shared_dpll_start_config() (Ville)
Restore old pll config if something fails before commit (Ville)
Don't set compute_clock hooks since dev_priv is kzalloc()'d (Ville)
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The new struct will be used in a follow up patch to allow a current and
a staged config to exist for the same shared DPLL.
v2: Rebase on by mask_to_refcount()->hweight32() change. (Damien)
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This will be used in a follow up patch to properly release shared DPLLs
without relying on the shared_dpll field in pipe_config.
v2: Fix white space error (Ville)
Use hweight32() (Ville)
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
When looking at the bug report logs with triggered
WARN_ON, the person doing bug triaging will have to
find exact kernel source and match file/line.
Attach the condition that triggered the WARN_ON
to kernel log. In most cases the context is self
evident and this way we can save developer time.
The drawback is ~16kbytes bigger i915.ko
Signed-off-by: Mika Kuoppala <miku@iki.fi>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Introduce functions to enable/disable the audio codec, incorporating the
ELD setup within enable. The disable is initially limited to HSW,
covering exactly what was done previously.
The only functional difference is that ELD valid is no longer set if
there is no connector with ELD, which should be the right thing to do
anyway. Otherwise the sequence remains the same, with warts and all, in
preparation for applying more sanity.
v2: add kernel doc.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This will simplify things later on. No functional changes.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
If these flags are on the object level it will be more difficult to allow
for multiple VMAs per object.
v2: Simplification and cleanup after code review comments (Chris Wilson).
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
By now we handle switcheroo and legacy suspend/resume the same way, so
no need to keep separate functions for them.
No functional change.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Some machines (like MBAs) might use a tiled framebuffer but not enable
display swizzling at boot time. We want to preserve that configuration
if possible to prevent a boot time mode set. On IVB+ it shouldn't
affect performance anyway since the memory controller does internal
swizzling anyway.
For most other configs we'll be able to enable swizzling at boot time,
since the initial framebuffer won't be tiled, thus we won't see any
corruption when we enable it.
v2: preserve swizzling if BIOS had it set (Daniel)
v3: preserve swizzling only if we inherited a tiled framebuffer (Daniel)
check display swizzle setting in detect_bit_6_swizzle (Daniel)
use gen6 as cutoff point (Daniel)
v4: fixup swizzle preserve again, had wrong init order (Daniel)
Reported-by: Kristian Høgsberg <hoegsberg@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
If we build the workaround list in ring initialization
and decouple it from the actual writing of values, we
gain the ability to decide where and how we want to apply
the values.
The advantage of this will become more clear when
we need to initialize workarounds on older gens where
it is not possible to write all the registers through ring
LRIs.
v2: rebase on newest bdw workarounds
Cc: Arun Siluvery <arun.siluvery@linux.intel.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Arun Siluvery <arun.siluvery@linux.intel.com>
[danvet: Resolve tiny conflict in comments and ocd alignments a bit.]
[danvet2: Remove bogus force_wake_get call spotted by Paulo and QA.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
For consistency, since that's the rule followed for internal functions.
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
For consistency, since that's the rule followed for internal functions.
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Just a couple more macros that assume that they were being passed a
struct drm_device when they want a struct drm_i915_private. Use our
magic macro to ease transitioning over to using drm_i915_privates
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Avoid to expose RC6 and RC6pp to the platforms that doesn't support it.
So powertop can be changed to show RC6p and RC6pp only on the platforms
they are available.
v2: Simplify by merging RC6p and RC6pp groups and respect the spec that
mentions deep and deepest RC6 on SNB and IVB although they keep disabled
by default.
v3: Remove unecessary space.
v4: RC6p and RC6pp is only for SNB and IVB; unify debug msg and use
has_rc6p() on sanitize options instead of is gen 6 and ivb.
v5: yet another fix on has_rc6p macro. final is_gen6 or is_ivb! To make sure
we are excluding hsw and baytrail.
References: https://bugs.freedesktop.org/show_bug.cgi?id=84524
Cc: Josh Triplett <josh.triplett@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
As stated in the few previous commits, IS_ULT/ULX() is better
per-platform as it has different consequences depending on the platform.
We now can get rid of it.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
HAS_IPS() has a '|| IS_BROADWELL()', no need to check for IS_BDW_ULT().
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Prep work for some nice documentation. Requires that we export the
display irq enable/disable functions on ilk/ibx. But we already export
them for vlv/i915. So not more inconsistency.
v2: Rebase on top of skl stage 1.
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
So I've sent the first pull request to Dave and I expect his request
for a merge tree any second now ;-)
More seriously I have some pending patches for 3.19 that depend upon
both trees, hence backmerge. Conflicts are all trivial.
Conflicts:
drivers/gpu/drm/i915/i915_irq.c
drivers/gpu/drm/i915/intel_display.c
v2: Of course I've forgotten the fixup script for the silent conflict.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
It's the new world order!
Not going full monty on these here and rolling this out throughout the
subsequent call chains since this is just for the kerneldoc. Later on
we can go more crazy, especially once we've embedded drm_device
correctly.
v2: Also frob the runtime_pm functions ...
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Double negations just parse harder. Also this allows us to ditch some
init code since clearing to 0 dtrt. Also ditch the assignment in
intel_pm_setup, that's not redundant since we do the assignement now
while setting up interrupts.
While at it do engage in a bit of OCD and wrap up the few lines of
setup/teardown code into little helper functions: intel_irq_fini for
cleanup and intel_irq_init_hw for hw setup.
v2: Use _install/_uninstall for the new wrapper function names as
Paulo suggested.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
- fini goes with init, so call it intel_power_domains_fini. While
at it shovel some of the fini code that leaked out of it back in.
- give power_enabled functions the verb _is_ to make the meaning clearer.
Also use a __ prefix instead of _unlocked to really discourage users.
- rename runtime_pm_init/fini to enable/disable since that's what they do.
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Another layer of indirection for just an lpt-only w/a is a bit
excessive. Reduce it.
This was added in
commit 7d708ee40a
Author: Imre Deak <imre.deak@intel.com>
Date: Wed Apr 17 14:04:50 2013 +0300
drm/i915: HSW: allow PCH clock gating for suspend
Cc: Imre Deak <imre.deak@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
SKL stage 1 patches still need polish so will likely miss the 3.18
merge window. We've decided to postpone to 3.19 so let's pull this in
to make patch merging and conflict handling easier.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
It will be usefull to specify w/a that affects only BDW GT3.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This reverts commit c76bb61a71.
It's apparently too broken so that Rodrigo submitted a patch to add a
config option for it. Given that the design is also ... suboptimal and
that I've only merged this to get lead engineers and managers off my
back for one second let's just revert this.
/me puts on combat gear again
It was worth a shot ...
References: http://mid.mail-archive.com/1411686380-1953-1-git-send-email-rodrigo.vivi@intel.com
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Daisy Sun <daisy.sun@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
The sw cache clean on BDW is a tempoorary workaround because we cannot
set cache clean on blt ring with risk of hungs. So we are doing the cache clean on sw.
However we are doing much more than needed. Not only when using blt ring.
So, with this extra w/a we minimize the ammount of cache cleans and call it only
on same cases that it was being called on gen7.
The traditional FBC Cache clean happens over LRI on BLT ring when there is a
frontbuffer touch happening. frontbuffer tracking set fbc_dirty variable
to let BLT flush that it must clean FBC cache.
fbc.need_sw_cache_clean works in the opposite information direction
of ring->fbc_dirty telling software on frontbuffer tracking to perform
the cache clean on sw side.
v2: Clean it a little bit and fully check for Broadwell instead of gen8.
v3: Rebase after frontbuffer organization.
v4: Wiggle confused me. So fixing v3!
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This can be useful to declare structures around pipes and planes and
don't have to go back auditing the code if the next platorm bump that
number.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Adding new macro IS_SKYLAKE for skylake specific implementation.
Reviewed-by: Thomas Wood <thomas.wood@intel.com>
Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
v2: Don't forget git add, noticed by David.
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Currently, calling intel_fbc_enabled() will trigger a register read.
And we call it a lot of times, even when FBC is disabled, so saving a
few cycles would be a good thing.
Another reason for this patch is because we currently call
intel_fbc_enabled() while the HW is runtime suspended, so the read
makes no sense and triggers a WARN. This happens even if FBC is
disabled by default. Of course one could argue that we just shouldn't
be calling intel_fbc_enabled() while the driver is runtime suspended,
and I agree that's a good argument, but I still think that the reason
explained in the first paragraph already justifies the patch.
This problem can easily be reproduced with many subtests of
igt/pm_rpm, and it is a regression introduced by:
commit c5ad011d7d
Author: Rodrigo Vivi <rodrigo.vivi@intel.com>
Date: Mon Aug 4 03:51:38 2014 -0700
drm/i915: FBC flush nuke for BDW
Testcase: igt/pm_rpm/cursor (and others)
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
