DP MST Link Check performed only for the connector involved with
HDCP port authentication and encryption, for other connector it
simply returns link check with true and update the uevent.
Therefore in case of HDCP 2.2 link failure, disable HDCP encryption
and de-authenticate the port so next time it can enable port
authentication and encryption.

Cc: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210319100208.5886-2-anshuman.gupta@intel.com

It requires to check streams type1 capability in mst topology
by checking Rxinfo instead connector HDCP2.x capability in
order to enforce type0 stream encryption in a mix of
HDCP {1.x,2.x} mst topology.
Rxcaps always shows HDCP 2.x capability of immediate downstream
connector. Let's use Rxinfo HDCP1_DEVICE_DOWNSTREAM bit to
detect a HDCP {1.x,2.x} mix mst topology.

Cc: Sean Paul <seanpaul@chromium.org>
Cc: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210319091732.17547-1-anshuman.gupta@intel.com

s/intel_/g4x_/ for the externally visible g4x_{dp,hdmi}.c
functions.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210318161015.22070-8-ville.syrjala@linux.intel.com

Extract the g4x+ HDMI low level code to its own file,
leaving intel_hdmi.c to deal with higher level issues.

The infoframe support I decided to leave in intel_hdmi.c
since I think we need to move that as a whole to its own file.
It is after all used also for DP SDPs, so no longer HDMI
specific.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210318161015.22070-7-ville.syrjala@linux.intel.com

Move the g4x+ DP code into a new file. This will leave mostly
platform agnostic code in intel_dp.c. Well, the misplaced phy
test stuff pretty much ruins that, but let's squint real hard
for now.

v2: Add comment exlaining which platforms are covered (Daniel)
    Leave intel_dp_unused_lane_mask() be since it is pretty generic

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210318161015.22070-6-ville.syrjala@linux.intel.com

Most of intel_dp_encoder_reset() is for pre-ddi platforms.
Make a clean split.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210318161015.22070-5-ville.syrjala@linux.intel.com

intel_dp_program_link_training_pattern() clearly belongs in
intel_dp_link_training.c. Make it so.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210318161015.22070-4-ville.syrjala@linux.intel.com

If we ever get here with bogus signal levels we've messed
up somewhere earlier. Just use MISSING_CASE().

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210318161015.22070-3-ville.syrjala@linux.intel.com

If we ever get here with TPS3 then intel_dp_training_pattern()
is just broken. Replace the careful fallback with just
MISSING_CASE().

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210318161015.22070-2-ville.syrjala@linux.intel.com

By the specification the 0xF0000 - 0xF02FF range is only valid if the
LTTPR revision at 0xF0000 is at least 1.4. Disable the LTTPR support
otherwise.

Fixes: 7b2a4ab8

 ("drm/i915: Switch to LTTPR transparent mode link training")
Cc: <stable@vger.kernel.org> # v5.11
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210317184901.4029798-4-imre.deak@intel.com

By the specification the 0xF0000-0xF02FF range is only valid when the
DPCD revision is 1.4 or higher. Disable LTTPR support if this isn't so.

Trying to detect LTTPRs returned corrupted values for the above DPCD
range at least on a Skylake host with an LG 43UD79-B monitor with a DPCD
revision 1.2 connected.

v2: Add the actual version check.
v3: Fix s/DRPX/DPRX/ typo.

Fixes: 7b2a4ab8

 ("drm/i915: Switch to LTTPR transparent mode link training")
Cc: <stable@vger.kernel.org> # v5.11
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210317190149.4032966-1-imre.deak@intel.com

The spec requires to use at least 3.2ms for the AUX timeout period if
there are LT-tunable PHY Repeaters on the link (2.11.2). An upcoming
spec update makes this more specific, by requiring a 3.2ms minimum
timeout period for the LTTPR detection reading the 0xF0000-0xF0007
range (3.6.5.1).

Accordingly disable LTTPR detection until GLK, where the maximum timeout
we can set is only 1.6ms.

Link training in the non-transparent mode is known to fail at least on
some SKL systems with a WD19 dock on the link, which exposes an LTTPR
(see the References below). While this could have different reasons
besides the too short AUX timeout used, not detecting LTTPRs (and so not
using the non-transparent LT mode) fixes link training on these systems.

While at it add a code comment about the platform specific maximum
timeout values.

v2: Add a comment about the g4x maximum timeout as well. (Ville)

Reported-by: Takashi Iwai <tiwai@suse.de>
Reported-and-tested-by: Santiago Zarate <santiago.zarate@suse.com>
Reported-and-tested-by: Bodo Graumann <mail@bodograumann.de>
References: https://gitlab.freedesktop.org/drm/intel/-/issues/3166
Fixes: b30edfd8

 ("drm/i915: Switch to LTTPR non-transparent mode link training")
Cc: <stable@vger.kernel.org> # v5.11
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210317184901.4029798-2-imre.deak@intel.com

s/nothign/nothing/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210319043701.14105-1-unixbhaskar@gmail.com

Remove code for resetting frl related members from intel_disable_dp, as
this is not applicable for older platforms.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210309043915.1921-3-ankit.k.nautiyal@intel.com

Add intel_bios_encoder_data pointer to encoder, and use it for hdmi and
dp iboost. For starters, we only set the encoder->devdata for DDI
encoders, i.e. we can only use it for data that is used by DDI encoders.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4bc49244ce68e136e5b21db4c4e6554bec9ac0fb.1615998927.git.jani.nikula@intel.com

Stop caching the information in ddi_port_info. We're phasing out
ddi_port_info usage completely, and prefer using the VBT child device
information directly using the provided helpers.

v2:
- Remove supports_typec_usb & supports_tbt from ddi_vbt_port_info (Lucas)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b04bd183e7554aeb4bc3962af90d63171aa32fc2.1615998927.git.jani.nikula@intel.com

Start using struct intel_bios_encoder_data directly. We'll start
sanitizing the child device data directly as well, instead of the cached
data in ddi_port_info[]. The one downside here is having to store a
non-const pointer back to intel_bios_encoder_data.

Eventually we'll be able to have a direct pointer from encoder to
intel_bios_encoder_data, removing the need to go through the
ddi_port_info[] array altogether. And we'll be able to remove all the
cached data in ddi_port_info[].

v2:
- Remove supports_dp and supports_edp from ddi_port_info too
- Add devdata != NULL check in intel_bios_is_port_edp()

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> # v1
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/061df32a012ff640060920fcd730fb23f8717ee8.1615998927.git.jani.nikula@intel.com

We'll be needing the intel_bios_encoder_data pointer going forward, and
it's just easier to store the higher level pointer in the
ddi_vbt_port_info[] array.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/89717516e99afccfecf1a7c6c938b8349f65e985.1615998927.git.jani.nikula@intel.com

These will be exposed to the rest of the driver and replace other
functions. Everything will operate on the child devices.

v2:
- Rebased, removed stray blank line
- Also abstracted intel_bios_encoder_supports_crt (Lucas)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/2bd40ccc093796d16300742d1789d78ffac3c450.1615998927.git.jani.nikula@intel.com

We'll be needing it in the future.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/026b737b122273d256f4247e9b0c84529aa391fd.1615998927.git.jani.nikula@intel.com

Make the naming suitable for exposing to the rest of the driver as an
opaque type. No functional changes.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/cb97c858de6e6afa96092db6d96e685fda006984.1615998927.git.jani.nikula@intel.com

Instead of initialing data directly in ddi_port_info array, create fake
child devices for default outputs when the VBT is missing. This makes
further unification of output handling easier.

This will make intel_bios_is_port_present() return true for the fake
child devices. This may cause subtle changes in a handful of places.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/91675b40a78bd04bf138598d979661257181880d.1615998927.git.jani.nikula@intel.com

There are two main cases where the default outputs are useful when the
VBT is missing:

- There are some DDI-platform Chromebooks out there that do not have a
  VBT, which worked by coincidence because of the default outputs. The
  machines need to continue to work.

- Early platform enabling when the VBT might not be available. (This
  could be circumvented by using the i915.vbt_firmware parameter.)

Prepare for generating fake child devices for the default outputs by
limiting the number of outputs. We don't want to generate excessive
amounts of fake child devices. This could be perhaps be limited even
more in the future, but match what's possible on all DDI platforms.

Note that limiting the defaults to non-TypeC ports in commit
828ccb31

 ("drm/i915/icl: Add TypeC ports only if VBT is present") is
a more strict limit, and makes this a no-op on recent platforms.

v2: Rewrote commit message

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5c9c9743af1c7265a2c976d582b7a6685ec0c414.1615998927.git.jani.nikula@intel.com

Pre-DDI and non-CHV aren't using the information created here anyway, so
don't bother setting the defaults for them. This should be a
non-functional change, but is separated here to catch any regressions in
a single commit.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: 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/41526a4eee5fb0de8d7f1ffe4c09965b63ccbaa8.1615998927.git.jani.nikula@intel.com

Unify the code paths at the higher level.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/44559ef456015f65a863c3d89a9bea9157d13a05.1615998927.git.jani.nikula@intel.com

Reduce indent with an early return. No functional changes.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
[Jani: fixed a couple of comment typos while applying.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/17288137452f731a820e737582672f836660a26f.1615998927.git.jani.nikula@intel.com

We'll be needing the version in more places in the future, so avoid the
need to pass it around. No functional changes.

v2: Rebased

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> # v1
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c2a4189241bf0946d27e12804b1ba7d098c7d483.1615998927.git.jani.nikula@intel.com

Time to just yank out the bandage. No functional changes.

v2: Rebased

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> # v1
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/93fe9e8be2e6120b085d09e49aafdf52f5ccd725.1615998927.git.jani.nikula@intel.com

It's the adls_revid_step_tbl array indexes that matter.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/996274d28cf939186a748b4714872b1c31b23adb.1615211711.git.jani.nikula@intel.com

gvt-next-2021-03-16

- Parse accurate vGPU virtual display rate (Colin)
- Convert vblank timer as per-vGPU based on current rate (Colin)
- spelling fix (Bhaskar)

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
From: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210316074330.GC1551@zhen-hp.sh.intel.com

One instance of DRM_DEBUG_KMS was leftover in dp_link_training, convert
it to the new shiny.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
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/20210310214845.29021-2-sean@poorly.run

This patch adds some newlines which are missing from debug messages.
This will prevent logs from being stacked up in dmesg.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
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/20210310214845.29021-1-sean@poorly.run

SAMPLE_OA parameter enables sampling of OA buffer and results in a call
to init the OA buffer which initializes the OA unit head/tail pointers.
The OA_EXPONENT parameter controls the periodicity of the OA reports in
the OA buffer and results in starting a hrtimer.

Before gen12, all use cases required the use of the OA buffer and i915
enforced this setting when vetting out the parameters passed. In these
platforms the hrtimer was enabled if OA_EXPONENT was passed. This worked
fine since it was implied that SAMPLE_OA is always passed.

With gen12, this changed. Users can use perf without enabling the OA
buffer as in OAR use cases. While an OAR use case should ideally not
start the hrtimer, we see that passing an OA_EXPONENT parameter will
start the hrtimer even though SAMPLE_OA is not specified. This results
in an uninitialized OA buffer, so the head/tail pointers used to track
the buffer are zero.

This itself does not fail, but if we ran a use-case that SAMPLED the OA
buffer previously, then the OA_TAIL register is still pointing to an old
value. When the timer callback runs, it ends up calculating a
wrong/large number of available reports. Since we do a spinlock_irq_save
and start processing a large number of reports, NMI watchdog fires and
causes a crash.

Start the timer only if SAMPLE_OA is specified.

v2:
- Drop SAMPLE OA check when appending samples (Ashutosh)
- Prevent read if OA buffer is not being sampled

Fixes: 00a7f0d7

 ("drm/i915/tgl: Add perf support on TGL")
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210305210947.58751-1-umesh.nerlige.ramappa@intel.com

Rename a bunch of the skl+ watermark struct members to
have sensible names. Avoids me having to think what
plane_res_b/etc. means.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210305153610.12177-7-ville.syrjala@linux.intel.com


Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

Make the code more typo proof by extracting small helpers that
do the "do we have enough DDB for the WM level?" checks in
a consistent manner.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210305153610.12177-6-ville.syrjala@linux.intel.com


Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

Let's make all the "do we have enough DDB for this WM level?"
checks use min_ddb_alloc. To achieve that we need to populate
this for the transition watermarks as well.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210305153610.12177-5-ville.syrjala@linux.intel.com


Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

For non-transition watermarks we are supposed to check min_ddb_alloc
rather than plane_res_b when determining if we have enough DDB space
for it. A bit too much copy pasta made me check the wrong thing.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Fixes: df4a50a3

 ("drm/i915: Zero out SAGV wm when we don't have enough DDB for it")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210305153610.12177-4-ville.syrjala@linux.intel.com


Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

Say we have two planes enabled with watermarks configured
as follows:
plane A: wm0=enabled/can_sagv=false, wm1=enabled/can_sagv=true
plane B: wm0=enabled/can_sagv=true,  wm1=disabled

This is possible since the latency we use to calculate
can_sagv may not be the same for both planes due to
skl_needs_memory_bw_wa().

In this case skl_crtc_can_enable_sagv() will see that
both planes have enabled at least one watermark level
with can_sagv==true, and thus proceeds to allow SAGV.
However, since plane B does not have wm1 enabled
plane A can't actually use it either. Thus we are
now running with SAGV enabled, but plane A can't
actually tolerate the extra latency it imposes.

To remedy this only allow SAGV on if the highest common
enabled watermark level for all active planes can tolerate
the extra SAGV latency.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210305153610.12177-3-ville.syrjala@linux.intel.com


Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

On HSW/BDW with VT-d active the first tile row scanned out
after the first async flip of the frame often ends up corrupted.

Whether the corruption happens or not depends on the scanline
on which the async flip happens, but the behaviour seems very
consistent. Ie. the same set of scanlines (which are most scanlines)
always show the corruption. And another set of scanlines (far less
of them) never shows the corruption.

I discovered that disabling the fetch-stride stretching
feature cures the corruption. This is some kind of TLB related
prefetch thing AFAIK. We already disable it on SNB primary
planes due to a documented workaround. The hardware folks
indicated that disabling this should be fine, so let's go
with that.

And while we're here, let's document the relevant bits on all
pre-skl platforms.

Fixes: 2a636e24 ("drm/i915: Implement async flip for ivb/hsw")
Fixes: cda195f1

 ("drm/i915: Implement async flips for bdw")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210220103303.3448-1-ville.syrjala@linux.intel.com


Reviewed-by: Karthik B S <karthik.b.s@intel.com>

Let's check that we actually found the PLL before doing the
port_clock readout, just in case the hardware was severly
misprogrammed by the previous guy. Not sure the hw would
even survive such misprogramming without hanging but no
real harm in checking anyway.

Cc: Karthik B S <karthik.b.s@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210310194351.6233-1-ville.syrjala@linux.intel.com


Reviewed-by: Karthik B S <karthik.b.s@intel.com>