Currently tests modify i915.enable_psr and then do a modeset cycle
to change PSR. We can write a value to i915_edp_psr_debug to force
a certain PSR mode without a modeset.
To retain compatibility with older userspace, we also still allow
the override through the module parameter, and add some tracking
to check whether a debugfs mode is specified.
Changes since v1:
- Rename dev_priv->psr.enabled to .dp, and .hw_configured to .enabled.
- Fix i915_psr_debugfs_mode to match the writes to debugfs.
- Rename __i915_edp_psr_write to intel_psr_set_debugfs_mode, simplify
it and move it to intel_psr.c. This keeps all internals in intel_psr.c
- Perform an interruptible wait for hw completion outside of the psr
lock, instead of being forced to trywait and return -EBUSY.
Changes since v2:
- Rebase on top of intel_psr changes.
Changes since v3:
- Assign psr.dp during init. (dhnkrn)
- Add prepared bool, which should be used instead of relying on psr.dp. (dhnkrn)
- Fix -EDEADLK handling in debugfs. (dhnkrn)
- Clean up waiting for idle in intel_psr_set_debugfs_mode.
- Print PSR mode when trying to enable PSR. (dhnkrn)
- Move changing psr debug setting to i915_edp_psr_debug_set. (dhnkrn)
Changes since v4:
- Return error in _set() function.
- Change flag values to make them easier to remember. (dhnkrn)
- Only assign psr.dp once. (dhnkrn)
- Only set crtc_state->has_psr on the crtc with psr.dp.
- Fix typo. (dhnkrn)
Changes since v5:
- Only wait for PSR idle on the PSR connector correctly. (dhnkrn)
- Reinstate WARN_ON(drrs.dp) in intel_psr_enable. (dhnkrn)
- Remove stray comment. (dhnkrn)
- Be silent in intel_psr_compute_config on wrong connector. (dhnkrn)
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180809142101.26155-1-maarten.lankhorst@linux.intel.com
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
In commit "drm/i915: Wait for PSR exit before checking for vblank
evasion", the idea was to limit the PSR IDLE checks when PSR is
actually supported. While CAN_PSR does do that check, it doesn't
applies on a per-crtc basis. crtc_state->has_psr is a more granular
check that only applies to pipe(s) that have PSR enabled.
Without the has_psr check, we end up waiting on the eDP transcoder's
PSR_STATUS register irrespective of whether the pipe being updated is
driving it or not.
v2: Remove unnecessary parantheses, make checkpatch happy.
v3: Move the has_psr check to intel_psr_wait_for_idle and commit
message changes (DK).
v4: Derive dev_priv from intel_crtc_state (DK)
v5: Commit message changes to reflect the HW behavior (DK)
Fixes: a608987970 ("drm/i915: Wait for PSR exit before checking for vblank evasion")
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Tarun Vyas <tarun.vyas@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712053323.26266-1-tarun.vyas@intel.com
This is a lockless version of the exisiting psr_wait_for_idle().
We want to wait for PSR to idle out inside intel_pipe_update_start.
At the time of a pipe update, we should never race with any psr
enable or disable code, which is a part of crtc enable/disable.
The follow up patch will use this lockless wait inside pipe_update_
start to wait for PSR to idle out before checking for vblank evasion.
We need to keep the wait in pipe_update_start to as less as it can be.
So,we can live and flourish w/o taking any psr locks at all.
Even if psr is never enabled, psr2_enabled will be false and this
function will wait for PSR1 to idle out, which should just return
immediately, so a very short (~1-2 usec) wait for cases where PSR
is disabled.
v2: Add comment to explain the 25msec timeout (DK)
v3: Rename psr_wait_for_idle to __psr_wait_for_idle_locked to avoid
naming conflicts and propagate err (if any) to the caller (Chris)
v5: Form a series with the next patch
v7: Better explain the need for lockless wait and increase the max
timeout to handle refresh rates < 60 Hz (Daniel Vetter)
v8: Rebase
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Tarun Vyas <tarun.vyas@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180627200250.1515-1-tarun.vyas@intel.com
Sink can be configured to calculate the CRC over the static frame and
compare with the CRC calculated and transmited in the VSC SDP by
source, if there is a mismatch sink will do a short pulse in HPD
and set DP_PSR_LINK_CRC_ERROR in DP_PSR_ERROR_STATUS.
Spec: 7723
v6:
andling DP_PSR_LINK_CRC_ERROR here and remove "bdw+" from commit
message
v4:
patch moved to after 'drm/i915/psr: Avoid PSR exit max time timeout'
to avoid touch in 2 patches EDP_PSR_DEBUG.
v3:
disabling PSR instead of exiting on error
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180626201644.21932-5-jose.souza@intel.com
Specification requires that max time should be masked from bdw and
forward but it can be also safely enabled to hsw.
This will make PSR exits more deterministic and only when really
needed. If this was used to fix a issue in some panel than can
only self-refresh for a few seconds, that panel will interrupt
and assert one of the PSR errors handled in:
'drm/i915/psr: Handle PSR RFB storage error' and
'drm/i915/psr: Begin to handle PSR/PSR2 errors set by sink'
Spec: 21664
v4:
patch moved to before 'drm/i915/psr/bdw+: Enable CRC check in the
static frame on the sink side' to avoid touch in 2 patches
EDP_PSR_DEBUG.
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180626201644.21932-4-jose.souza@intel.com
eDP spec states that sink device will do a short pulse in HPD
line when there is a PSR/PSR2 error that needs to be handled by
source, this is handling the first and most simples error:
DP_PSR_SINK_INTERNAL_ERROR.
Here taking the safest approach and disabling PSR(at least until
the next modeset), to avoid multiple rendering issues due to
bad pannels.
v5:
added lockdep_assert in psr_disable and renamed psr_disable()
to intel_psr_disable_locked()
v4:
Using CAN_PSR instead of HAS_PSR in intel_psr_short_pulse
v3:
disabling PSR instead of exiting on error
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180626201644.21932-2-jose.souza@intel.com
Commit 5422b37c90 ("drm/i915/psr: Kill delays when activating psr
back.") switched from delayed work to the plain variant and while doing so
removed the check for work_busy() before scheduling a PSR activation.
This appears to cause consecutive executions of psr_activate() in this
scenario - after a worker picks up the PSR work item for execution and
before the work function can acquire the PSR mutex, a psr_flush() can
get hold of the mutex and schedule another PSR work. Without a psr_exit()
between the two psr_activate() calls, warning messages get printed.
Further, since we drop the mutex in the midst of psr_work() to wait for
PSR to idle, another work item can also get scheduled. Fix this by
returning if PSR was already active.
Fixes: 5422b37c90 ("drm/i915/psr: Kill delays when activating psr back.")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106948
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180625054741.3919-1-dhinakaran.pandiyan@intel.com
So far we got an AUX power domain reference only for the duration of DP
AUX transfers. However, the following suggests that we also need these
for main link functionality:
- The specification doesn't state whether it's needed or not for main
link functionality, but suggests that these power wells need to be
enabled already during display core initialization (Sequences to
Initialize Display).
- For PSR we need to keep the AUX power well enabled.
- On ICL combo PHY ports (non-TC) the AUX power well is needed for
link training too: while the port is enabled with a DP link training
test pattern trying to toggle the AUX power well will time out.
- On ICL MG PHY ports (TC) the AUX power well is needed also for main
link functionality (both in DP and HDMI modes).
- Windows enables these power wells both for main and AUX lane
functionality.
Based on the above take an AUX power reference for main link
functionality too. This makes a difference only on GEN10+ (GLK+)
platforms, where we have separate port specific AUX power wells.
For PSR we still need to distinguish between port A and the other
ports, since on port A DC states must stay enabled for main link
functionality, but DC states must be disabled for driver initiated
AUX transfers. So re-use the corresponding helper from intel_psr.c.
Since we take now a reference for main link functionality on all DP
ports we can forgo taking the separate power ref for PSR functionality.
v2:
- Make sure DC states stay enabled when taking the ref on port A.
(Ville)
v3: (Ville)
- Fix comment about logic for encoders without a crtc state and
add FIXME note for a simplification to avoid calling get_power_domains
in such cases.
- Use intel_crtc_has_dp_encoder() instead !intel_crtc_has_type(HDMI).
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
[Clarified code comments in intel_ddi_main_link_aux_domain() and
intel_ddi_get_power_domains() (Imre)]
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180621184449.26634-1-imre.deak@intel.com
The immediate enabling was actually not an issue for the
HW perspective for core platforms that have HW tracking.
HW will wait few identical idle frames before transitioning
to actual psr active anyways.
Now that we removed VLV/CHV out of the picture completely
we can safely remove any delays.
Note that this patch also remove the delayed activation
on HSW and BDW introduced by commit 'd0ac896a477d
("drm/i915: Delay first PSR activation.")'. This was
introduced to fix a blank screen on VLV/CHV and also
masked some frozen screens on other core platforms.
Probably the same that we are now properly hunting and fixing.
v2:(DK): Remove unnecessary WARN_ONs and make some other
VLV | CHV more readable.
v3: Do it regardless the timer rework.
v4: (DK/CI): Add VLV || CHV check on cancel work at psr_disable.
v5: Kill remaining items and fully rework activation functions.
v6: Rebase on top of VLV/CHV clean-up and keep the reactivation
on a regular non-delayed work to avoid extra delays on exit
calls and allow us to add few more safety checks before
real activation.
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180613192600.3955-1-rodrigo.vivi@intel.com
DPCD 2009h "Synchronization latency in sink" has bits that tell us the
maximum number of frames sink can take to resynchronize to source timing
when exiting PSR. More importantly, as per eDP 1.4b, this is the "Minimum
number of frames following PSR exit that the Source device needs to
wait for PSR entry."
We currently use this value only to setup the number frames to wait before
PSR2 selective update. But, based on the above description it makes more
sense to use this to configure idle frames for both PSR1 and and PSR2. This
will ensure we wait the required number of frames before
activation whether it is PSR1 or PSR2.
The minimum number of idle frames remains 6, while allowing sink
synchronization latency and VBT to increase this value.
This also solves the flip-flop between sink and source frames that I
noticed on my Thinkpad X260 during PSR exit. This specific panel has a
value of 8h, which according to the spec means the "Source device must
wait for more than eight active frames after PSR exit before initiating PSR
entry. (In this case, should be provided by the panel supplier.)" VBT
however has a value of 0.
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jose Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180525033047.7596-1-dhinakaran.pandiyan@intel.com
PSR hardware and hence the driver code for VLV and CHV deviates a lot from
their DDI counterparts. While the feature has been disabled for a long time
now, retaining support for these platforms is a maintenance burden. There
have been multiple refactoring commits to just keep the existing code for
these platforms in line with the rest. There are known issues that need to
be fixed to enable PSR on these platforms, and there is no PSR capable
platform in CI to ensure the code does not break again if we get around to
fixing the existing issues. On account of all these reasons, let's nuke
this code for now and bring it back if a need arises in the future.
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180511230059.19387-1-dhinakaran.pandiyan@intel.com
For psr block #9, the vbt description has moved to options [0-3] for
TP1,TP2,TP3 Wakeup time from decimal value without any change to vbt
structure. Since spec does not mention from which VBT version this
change was added to vbt.bsf file, we cannot depend on bdb->version check
to change for all the platforms.
There is RCR inplace for GOP team to provide the version number
to make generic change. Since Kabylake with bdb version 209 is having this
change, limiting this change to gen9_bc and version 209+ to unblock google.
Tested on skl(bdb version 203,without options) and
kabylake(bdb version 209,212) having new options.
bspec 20131
v2: (Jani and Rodrigo)
move the 165 version check to intel_bios.c
v3: Jani
Move the abstraction to intel_bios.
v4: Jani
Rename tp*_wakeup_time to have "us" suffix.
For values outside range[0-3],default to max 2500us.
Old decimal value was wake up time in multiples of 100us.
v5: Jani and Rodrigo
Handle option 2 in default condition.
Print oustide range value.
For negetive values default to 2500us.
v6: Jani
Handle default first and then fall through for case 2.
v7: Rodrigo
Apply this change for IS_GEN9_BC and vbt version > 209
v8: Puthik
Add new function vbt_psr_to_us.
v9: Jani
Change to v7 version as it's more readable.
DK
add comment /*fall through*/ after case2.
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Puthikorn Voravootivat <puthik@chromium.org>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Maulik V Vaghela <maulik.v.vaghela@intel.com>
Signed-off-by: Vathsala Nagaraju <vathsala.nagaraju@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1526981243-2745-1-git-send-email-vathsala.nagaraju@intel.com
Any write in any display register was causing HW to exit PSR,
masking it to allow more power savings. Writes to pipe related
registers will still cause HW to exit PSR.
This is already masked for PSR2.
It also do not break the Display WA #0884, writes to CURSURFLIVE
are still causing hardware to exit PSR. This was tested in CNL machine
by triggering a write to CURSURFLIVE when a debugfs was read by user.
Bspec: 7721 and 8042
v4: Checked that it do not breaks WA #0884 and added this information
to the commit message.
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180425212334.21109-1-jose.souza@intel.com
Interrupts other than the one for AUX errors are required only for debug,
so unmask them via debugfs when the user requests debug.
User can make such a request with
echo 1 > <DEBUG_FS>/dri/0/i915_edp_psr_debug
There are no locks to serialize PSR debug enabling from
irq_postinstall() and debugfs for simplicity. As irq_postinstall() is
called only during module initialization/resume and IGT subtests
aren't expected to modify PSR debug at those times, we should be safe.
v2: Unroll loops (Ville)
Avoid resetting error mask bits.
v3: Unmask interrupts in postinstall() if debug was still enabled.
Avoid RMW (Ville)
v4: Avoid extra IMR write introduced in the previous version.(Jose)
Style changes, renames (Jose).
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Jose Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180405013717.24254-1-dhinakaran.pandiyan@intel.com
Although i915 don't implement aux sync frame through tests was
findout that pannels can do selective update when the y-coordinate
is also included in SDP, that is why it is required to run PSR2 in
i915.
So moving to only one place the sink requirements that the actual
driver needs to enable PSR2.
Also intel_psr2_config_valid() is called every time the crtc config
is computed, wasting some time every time it was checking for
Y coordinate requirement.
This allow us to nuke y_cord_support and some of VSC setup code that
was handling a scenario that would never happen(PSR2 without Y
coordinate).
Also here renaming intel_dp_get_y_cord_status() to
intel_dp_get_y_coord_required() as it more accurate to the name and
function of bit according to eDP spec.
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180328223046.16125-4-jose.souza@intel.com
eDP spec states that aux frame is required to do PSR2 selective
update but i915 don't fully implement it. It sends the aux frame
sync messages but the value is always zero as the GTC is not enabled
in driver.
Through tests was findout that pannels can do selective update when
the y-coordinate is also included in SDP, that is why it is required
to run PSR2 in i915.
A dummy value is not useful at all to sink, so removing everything
related to aux frame sync, if GTC is enabled we can bring this back.
Cc: Vathsala Nagaraju <vathsala.nagaraju@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180328223046.16125-3-jose.souza@intel.com
HSW and BDW have SRD_AUX_{CTL, STATUS} registers that the driver needs to
setup for the HW to use whenever exiting PSR. SKL+ hardware use hardcoded
values for the same and do not need any registers to be setup. So, use
drm_dp_dpcd_writeb() for a one-time write during PSR enable and setup the
PSR aux registers on HSW and BDW for later use by HW.
We also end up writing to reserved bits in SRD_AUX_CTL by reusing
intel_dp->get_aux_send_ctl() for HSW and BDW, fix this.
Since the AUX register setup is source side programming, move the call
to enable_source() from enable_sink().
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Jose Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180313034646.3721-2-dhinakaran.pandiyan@intel.com
So far we are using frontbuffer tracking for everything
and ignoring that PSR has a HW capable HW tracking for many
modern usages of GPU on Core platforms and newer Atom ones.
One reason for that is that we were trying to keep same
infrastructure in place for VLV/CHV than the rest of platforms.
But also because when this infrastructure was created
the front-buffer-tracking origin wasn't that good and stable
how it is today after Paulo reworked it to attend FBC cases.
However this PSR implementation without HW tracking died
on gen8LP. And newer platforms are starting to demand more HW
tracking specially with PSR2 cases in mind.
By disabling and re-enabling PSR totally every time we believe
someone is going to change the front buffer content we don't
allow PSR HW tracking to do this job and specially compromising
the whole idea of PSR2 case where the HW tracking detect only
the damaged area and do a partial screen update.
So, from now on, on the platforms that has hw_tracking let's
rely more on HW tracking.
This also is the case in used by other drivers and more validated
by SV teams. So I hope that this will lead us to less misterious
bugs.
v2: Only do this for platform that actually has hw tracking.
v3 from DK
Do this only for flips, small gradual changes are better.
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Jim Bride <jim.bride@linux.intel.com>
Cc: Vathsala Nagaraju <vathsala.nagaraju@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Jose Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307033420.3086-3-dhinakaran.pandiyan@intel.com
WA 0884:bxt:all,cnl:*:A - "When FBC is enabled with eDP PSR,
the CPU host modify writes may not get updated on the Display
as expected.
WA: Write 0x00000000 to CUR_SURFLIVE_A with every CPU
host modify write to trigger PSR exit."
We can also find on spec other cases where they describe
bogus writes to cursor registers to force PSR exit with
HW tracking. And it was confirmed by HW engineers that
this Wa can be safely applied for any frontbuffer activity.
So let's use this more and more here instead of forcibly
disable and re-enable PSR everytime that we have a simple
reliable flush case.
Other commits improve the fbcon/fbdev use a lot, but this
approach is the only when where we can get a fully reliable
console with no slowness or missed frames and PSR still
enabled and active.
v2: - Rebase on drm-tip
- (DK) Add a comment to explain that WA
tells about writing 0 to CUR_SURFLIVE_A but we write to
CUR_SURFLIVE(pipe).
v3: Wa doesn't work on PSR2.
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180309005218.26772-1-rodrigo.vivi@intel.com
