There are a few good properties to a circular buffer, for instance it
has a number of entries (before we were always dumping the full buffer).
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Note the "return -ENODEV;" in pipe_crc_set_source(). The ctl file is
disabled until the end of the series to be able to do incremental
improvements.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
There are several points in the display pipeline where CRCs can be
computed on the bits flowing there. For instance, it's usually possible
to compute the CRCs of the primary plane, the sprite plane or the CRCs
of the bits after the panel fitter (collectively called pipe CRCs).
v2: Quite a bit of rework here and there (Damien)
Signed-off-by: Shuang He <shuang.he@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Fix intermediate compile file reported by Wu Fengguang's
kernel builder.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
I've sent this patch several times for various reasons. It essentially
cleans up a lot of code where we need to do something per ring, and want
to query whether or not the ring exists on that hardware.
It has various uses coming up, but for now it shouldn't be too
offensive.
v2: Big conflict resolution on Damien's DEV_INFO_FOR_EACH stuff
v3: Resolved vebox addition
v4: Rebased after months of disuse. Also made failed ringbuffer init
cleaner.
v5: Remove the init cleaner from v4. There is a better way to do it.
(Chris)
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
I had this lying around from he original PPGTT series, and thought we
might try to get it in by itself.
With the introduction of context refcounting we never explicitly
ref/unref the backing object. As such, the previous fix was a bit wonky.
Aside from fixing the above, this patch also puts us in good shape for
an upcoming patch which allows a failure to occur in between
context_init and the first do_switch.
CC: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
I had this lying around from he original PPGTT series, and thought we
might try to get it in by itself.
It's convenient to just call i915_gem_init_hw at reset because we'll be
adding new things to that function, and having just one function to call
instead of reimplementing it in two places is nice.
In order to accommodate we cleanup ringbuffers in order to bring them
back up cleanly. Optionally, we could also teardown/re initialize the
default context but this was causing some problems on reset which I
wasn't able to fully debug, and is unnecessary with the previous context
init/enable split.
This essentially reverts:
commit 8e88a2bd59
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Tue Jun 19 18:40:00 2012 +0200
drm/i915: don't call modeset_init_hw in i915_reset
It seems to work for me on ILK now. Perhaps it's due to:
commit 8a5c2ae753
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Thu Mar 28 13:57:19 2013 -0700
drm/i915: fix ILK GPU reset for render
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Using the 5/6 DDB split make sense only when sprites are enabled.
So check that before we waste any cycles computing the merged
watermarks with the 5/6 DDB split.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Makes the behaviour of the function more clear.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Makes the intention more clear.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We want to be able to use the masks to decode the register contents
regardless of the hardware generation. So just expand the masks to
cover all available bits, even if those are reserved on some
generations.
v2: Don't extend WM1_LP_SR_MASK so far, for the *future*
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This debug print just adds overhead to the watermark merging process,
and doesn't really give enough information to be useful. Just kill
and let's add something much better a bit later.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Fill out the HSW watermark s/w tracking structures with the current
hardware state in intel_modeset_setup_hw_state(). This allows us to skip
the HW state readback during watermark programming and just use the values
we keep around in dev_priv->wm. Reduces the overhead of the watermark
programming quite a bit.
v2: s/init_wm/wm_get_hw_state
Remove stale comment about sprites
Make DDB partitioning readout safer
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Fix whitespace fail.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Currently hsw_write_vm_values() may write to certain watermark
registers needlessly. For instance if only, say, LP3 changes,
the current code will again disable all LP1+ watermarks even
though only LP3 needs to be reconfigured.
Add an easy to read function that will compute the dirtyness of the
watermarks, and use that information to further optimize the watermark
programming.
v2: Disable LP1+ watermarks around changing LP0 watermarks for Paulo
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
To make it easier to check what watermark updates are actually
necessary, keep copies of the relevant bits that match the current
hardware state.
Also add DDB partitioning into hsw_wm_values as that's another piece
of state we want to track.
We don't read out the hardware state on init yet, so we can't really
start using this yet, but it will be used later.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Paulo asked for a comment around the memcmp to say that we
depend upon zero-initializing the entire structures due to padding.
But a later patch in this series removes the memcmp again. So this is
ok as-is.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The fbc_wm_enabled member in intel_wm_config is useless for the time
being. The original idea for it was that we'd pre-compute it and so
that the WM merging process could know whether it needs to worry
about FBC watermarks at all.
But we don't have a convenient way to pre-check for the possibility
of FBC being used. intel_update_fbc() should be split up for that.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
On HSW the LP1,LP2,LP3 levels are either 1,2,3 or 1,3,4. We make the
conversion from LPn to to the level at one point current. Later we're
going to do it in a few places, so move it to a separate function.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Using the 5/6 DDB split make sense only when sprites are enabled.
So check that before we waste any cycles computing the merged
watermarks with the 5/6 DDB split.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Move the watermark max computations into haswell_update_wm(). This
allows keeping the 1/2 vs. 5/6 split code in one place, and avoid having
to pass around so many things. We also save a bit of stack space by only
requiring one copy of struct hsw_wm_maximums.
Also move the intel_wm_config out from hsw_compute_wm_parameters() and
pass it it. We'll have some need for it in haswell_update_wm() later.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Let's try to keep using the intermediate intel_pipe_wm representation
for as long as possible. It avoids subtle knowledge about the
internals of the hardware registers when trying to choose the
best watermark configuration.
While at it replace the memset() w/ zero initialization.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
I want to convert hsw_find_best_result() to use intel_pipe_wm, so we
need to move the merging to happen outside hsw_compute_wm_results().
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
No point in re-computing the watermarks for all pipes, when only one
pipe has changed. The watermarks stored under intel_crtc.wm.active are
still valid for the other pipes. We just need to redo the merging.
We can also skip the merge/update procedure completely if the new
watermarks for the affected pipe come out unchanged.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Introduce a new struct intel_pipe_wm which contains all the
watermarks for a single pipe. Use it to unify the LP0 and LP1+
watermark computations so that we can just iterate through the
watermark levels neatly and call ilk_compute_wm_level() for each.
Also add another tool ilk_wm_merge() that merges the LP1+ watermarks
from all pipes. For that, embed one intel_pipe_wm inside intel_crtc that
contains the currently valid watermarks for each pipe.
This is mainly preparatory work for pre-computing the watermarks for
each pipe and merging them at a later time. For now the merging still
happens immediately.
v2: Add some comments about level 0 DDB split and intel_wm_config
Add WARN_ON for level 0 being disabled
s/lp_wm/merged
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Gen2 doesn't have a hardware frame counter that can be read out. Just
provide a stub .get_vblank_counter() that always returns 0 instead of
trying to read non-existing registers.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Gen2 doesn't have the pixelcount register that gen3 and gen4 have.
Instead we must use the scanline counter like we do for ctg+.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The DSL register increments at the start of horizontal sync, so it
manages to miss the entire active portion of the current line.
Improve the get_scanoutpos accuracy a bit when the scanout position is
close to the start or end of vblank. We can do that by double checking
the DSL value against the vblank status bit from ISR.
Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: mario.kleiner.de@gmail.com
Tested-by: mario.kleiner.de@gmail.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The reported scanout position must be relative to the end of vblank.
Currently we manage to fumble that in a few ways.
First we don't consider the case when vtotal != vbl_end. While that
isn't very common (happens maybe only w/ old panel fitting hardware),
we can fix it easily enough.
The second issue is that on pre-CTG hardware we convert the pixel count
to horizontal/vertical components at the very beginning, and then forget
to adjust the horizontal component to be relative to vbl_end. So instead
we should keep our numbers in the pixel count domain while we're
adjusting the position to be relative to vbl_end. Then when we do the
conversion in the end, both vertical _and_ horizontal components will
come out correct.
v2: Change position to int from u32 to avoid sign issues
Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: mario.kleiner.de@gmail.com
Tested-by: mario.kleiner.de@gmail.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We have all the information we need in the mode structure, so going and
reading it from the hardware is pointless, and slower.
We never populated ->get_vblank_timestamp() in the UMS case, and as that
is the only way we'd ever call ->get_scanout_position(), we can
completely ignore UMS in i915_get_crtc_scanoutpos().
Also reorganize intel_irq_init() a bit to clarify the KMS vs. UMS
situation.
v2: Drop UMS code
Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: mario.kleiner.de@gmail.com
Tested-by: mario.kleiner.de@gmail.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Rounding down when calculating the dot/vco frequencies doesn't make much
sense. Round to closest should give slightly nicer answers.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
At the moment we have 3 paths that lead to actually_set_backlight(),
from modesetting, ACPI/OpRegion requests and our very own
intel_backlight interface, and we have no way of distinguishing them in
the debug log. So add a debug breadcrumb to explain the source of the
backlight changes.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The old style frame counter increments at the start of active video.
However for i915_get_vblank_counter() we want a counter that increments
at the start of vblank.
Fortunately the low frame counter register also contains the pixel
counter for the current frame. We can can compare that against the
vblank start pixel count to determine if we need to increment the
frame counter by 1 to get the correct answer.
Also reorganize the function pointer assignments in intel_irq_init() a
bit to avoid confusing people.
Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This file is all about the legacy fbdev support. If we want to extract
framebuffer functions, we better put those into a separate file.
Also rename functions accordingly, only two have used the intel_fb_
prefix anyway.
Reviewed-by: Chon Ming Lee <chon.ming.lee@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Boots Just Fine (tm)!
The only glitch seems to be that at least on Fedora the boot splash
gets confused and doesn't display much at all.
And since there's no ugly console flickering anymore in between, the
flicker while switching between X servers (VT support is still enabled)
is even more jarring.
Also, I'm unsure whether we don't need to somehow kick out vgacon, now
that nothing else gets in the way. But stuff seems to work, so I
don't care. Also everything still works as well with VGA_CONSOLE=n
Also the #ifdef mess needs a bit of a cleanup, follow-up patches will
do just that.
To keep the Kconfig tidy, extract all the i915 options into its own
file.
v2:
- Rebase on top of the preliminary hw support option and the
intel_drv.h cleanup.
- Shut up warnings in i915_debugfs.c
v3: Use the right CONFIG variable, spotted by Chon Ming.
Cc: Lee, Chon Ming <chon.ming.lee@intel.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Chon Ming Lee <chon.ming.lee@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
For drivers which might want to disable fbdev legacy support.
Select the new option in all drivers for now, so this shouldn't result
in any change. Drivers need some work anyway to make fbdev support
optional (if they have it implemented, that is), so the recommended
way to expose this is by adding per-driver options. At least as long
as most drivers don't support disabling the fbdev support.
v2: Update for new drm drivers msm and rcar-du. Note that Rob's msm
driver can already take advantage of this, which allows us to build
msm without any fbdev depencies in the kernel!
v3: Move the MODULE_* stuff from the fbdev helper file to
drm_crtc_helper.c.
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Acked-by: Dave Airlie <airlied@linux.ie>
Reviewed-by: Chon Ming Lee <chon.ming.lee@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Supposedly VLV uses the CTG+ style frame counter registers instead of
the old gen3/4 style. Add the magic offset to the correct registers.
We should already be taking the correct codepaths for
.get_vblank_counter() and .get_scanout_position().
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
So digging out the right ones is a little easier.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
On gen7+, CACHE_MODE_0 moved, so we're clobbering some other reg rather
than restoring CACHE_MODE_0. Don't do that.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The current pre-gen4 pipe off code might break out of the loop
due to the timeout, but then the fail to print the warning.
Refactor the code a bit to use wait_for() to avoid the problem,
and that we also re-check the condition after the timeout has
expired.
v2: Use wait_for()
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The spec says the default timeout should be 2ms, but on my machine
this doesn't seem to be enough. Sometimes it works, sometimes I get
these messages when booting:
- SWSCI request timed out
- SWSCI request already in progress
And my guess is that the "already in progress" message is because the
first one is still happening.
I did some experiments on my machine (that has CONFIG_HZ=1000) and the
wait_for function usually takes 4-6 jiffies to finish, but I've seen
up to 9. So increase the timeout to 50ms. We only expect to wait for
the actual amount of time the operation takes, so even a huge timeout
shouldn't delay us more than what the hardware actually requires.
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
As we delay the initial RPS enabling (upon boot and after resume), there
is a chance that we may start to render and trigger RPS boosts before we
set up the punit. Any changes we make could result in inconsistent
hardware state, with a danger of causing undefined behaviour. However,
as the boosting is a optional tweak to RPS, we can simply ignore it
whilst RPS is not yet enabled.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Educate the users why i915 won't load on gen6+ and nomodeset.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=61671
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Untangling me-too reports that actually aren't is really messy. And we
need to make sure the blame is put where it should be right from the
start ;-)
v2: Improve the wording from Ben's suggestions.
Cc: Ben Widawsky <ben@bwidawsk.net>
Acked-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: Frob the message as suggested by Paulo on irc.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Enabling rps (turbo setup) was put in a work queue because it may
take quite awhile. This change flushes the work queue to initialize
rps values before use by sysfs or debugfs. Specifically,
rps.delayed_resume_work is flushed before using rps.hw_max,
rps.max_delay, rps.min_delay, or rps.cur_delay.
This change fixes a problem in sysfs where show functions using
uninitialized values show incorrect values and store functions
using uninitialized values in range checks incorrectly fail to
store valid input values. This change also addresses similar use
before initialized problems in debugfs.
Signed-off-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We lost the ability to capture the first error for a stuck ring in the
recent hangcheck robustification. Whilst both error states are
interesting (why does the GPU not recover is also essential to debug),
our primary goal is to fix the initial hang and so we need to capture
the first error state upon taking hangcheck action.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Let's try to avoid these confusing negated booleans.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Regression introduced by:
commit 311a20949f
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
drm/i915: don't init DP or HDMI when not supported by DDI port
Since the commit above it is possible to have a DDI encoder that has
the HDMI connector but not the DP connector (in case the port doesn't
support DP). In this case, we must properly free the DP connector.
We just leak this once, so it's not a big deal.
Reported by kmemleak.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The DP spec allows this, and requires it when full link training is
started with non-minimum voltage swing and/or non-zero pre-emphasis.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Damien Lespiau