linux-stable.git/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c, branch v6.18

drm/amd/display: Increase EDID read retries

2025-11-26T17:32:05+00:00

[WHY]
When monitor is still booting EDID read can fail while DPCD read
is successful.  In this case no EDID data will be returned, and this
could happen for a while.

[HOW]
Increase number of attempts to read EDID in dm_helpers_read_local_edid()
to 25.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4672
Cc: Mario Limonciello 
Cc: Alex Deucher 
Reviewed-by: Alex Hung 
Signed-off-by: Mario Limonciello (AMD) 
Signed-off-by: Alex Hung 
Tested-by: Dan Wheeler 
Signed-off-by: Alex Deucher 
(cherry picked from commit a76d6f2c76c3abac519ba753e2723e6ffe8e461c)
Cc: stable@vger.kernel.org

drm/amd/display: Add HDR workaround for a specific eDP

2025-10-28T15:04:40+00:00

[WHY & HOW]
Some eDP panels suffer from flicking when HDR is enabled in KDE or
Gnome.

This add another quirk to worksaround to skip VSC that is incompatible
with an eDP panel.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/4452
Reviewed-by: Aurabindo Pillai 
Signed-off-by: Alex Hung 
Signed-off-by: Wayne Lin 
Tested-by: Dan Wheeler 
Signed-off-by: Alex Deucher 
(cherry picked from commit 99441824bec63549a076cd86631d138ec9a0c71c)
Cc: stable@vger.kernel.org

drm/amd/display: Add missing SPDX license identifier

2025-07-28T20:40:30+00:00

[Why]
All files should be properly classified.

[How]
Add missing SPDX-License-Identifier.

Reviewed-by: Sun peng (Leo) Li 
Signed-off-by: Mario Limonciello 
Signed-off-by: Ivan Lipski 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher

drm/amd/display: Add sanity checks for drm_edid_raw()

2025-06-24T14:05:44+00:00

When EDID is retrieved via drm_edid_raw(), it doesn't guarantee to
return proper EDID bytes the caller wants: it may be either NULL (that
leads to an Oops) or with too long bytes over the fixed size raw_edid
array (that may lead to memory corruption).  The latter was reported
actually when connected with a bad adapter.

Add sanity checks for drm_edid_raw() to address the above corner
cases, and return EDID_BAD_INPUT accordingly.

Fixes: 48edb2a4256e ("drm/amd/display: switch amdgpu_dm_connector to use struct drm_edid")
Link: https://bugzilla.suse.com/show_bug.cgi?id=1236415
Signed-off-by: Takashi Iwai 
Signed-off-by: Alex Deucher

drm/amd/display: Fix ACPI edid parsing on some Lenovo systems

2025-04-22T12:51:44+00:00

[Why]
The ACPI EDID in the BIOS of a Lenovo laptop includes 3 blocks, but
dm_helpers_probe_acpi_edid() has a start that is 'char'.  The 3rd
block index starts after 255, so it can't be indexed properly.
This leads to problems with the display when the EDID is parsed.

[How]
Change the variable type to 'short' so that larger values can be indexed.

Cc: Renjith Pananchikkal 
Reported-by: Mark Pearson 
Suggested-by: David Ober 
Fixes: c6a837088bed ("drm/amd/display: Fetch the EDID from _DDC if available for eDP")
Reviewed-by: Alex Hung 
Signed-off-by: Mario Limonciello 
Signed-off-by: Zaeem Mohamed 
Tested-by: Mark Broadworth 
Signed-off-by: Alex Deucher

drm/amd/display: HDCP Locality check using DMUB Fused IO

2025-04-07T22:01:07+00:00

[Why]
HDCP locality check has strict timing requirements, currently broken
due to reliance on msleep which does not guarantee accuracy.
The PR moves the write-poll-read sequence into DMUB using new generic
Fused IO interface, where the timing accuracy is greatly improved.
New flow is enabled using DCN resource capability bit (none for now),
or using a debug flag.

[How]
* Extended mod_hdcp_config with new function for requesting DMUB
to execute a sequence of fused I2C/AUX commands and synchronously
wait until an outbox reply arrives or a timeout expires.
* If the timeout expires, send an abort to DMUB.
* Update HDCP to use the DMUB for locality check if supported.
* Add DC_HDCP_LC_FORCE_FW_ENABLE and DC_HDCP_LC_ENABLE_SW_FALLBACK.
* Make the first enable new flow regardless of resource capabilities.
* Make the second enable fallback to old SW flow.
* Clean up makefile source file listings for easier updates.

Reviewed-by: Alvin Lee 
Signed-off-by: Dominik Kaszewski 
Signed-off-by: Roman Li 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher

drm/amd/display: use drm_* instead of DRM_ in apply_edid_quirks()

2025-03-05T15:46:51+00:00

drm_* macros are more helpful that DRM_* macros since the former
indicates the associated DRM device that prints the error, which maybe
helpful when debugging.

Signed-off-by: Aurabindo Pillai 
Reviewed-by: Alex Hung 
Signed-off-by: Alex Deucher

drm/amd/display: Add workaround for a panel

2025-03-05T15:46:44+00:00

Implement w/a for a panel which requires 10s delay after link detect.

Signed-off-by: Aurabindo Pillai 
Reviewed-by: Alex Hung 
Signed-off-by: Alex Deucher

drm/amd/display: Add HBlank reduction DPCD write to DPMS sequence

2025-01-06T19:44:27+00:00

[Why]
Certain small HBlank timings may not have a large enough HBlank to
support audio when low bpp DSC is enabled. HBlank expansion by the
source can solve this problem, but requires the branch/sink to support
HBlank reduction.

[How]
Update DPMS sequence to call DM to perform DPCD write to enable HBlank
reduction on the branch/sink. Add stub in dm_helpers to be implemented
later.

Reviewed-by: Michael Strauss 
Reviewed-by: Wenjing Liu 
Signed-off-by: George Shen 
Signed-off-by: Roman Li 
Tested-by: Daniel Wheeler 
Signed-off-by: Alex Deucher

drm/amd: Sanity check the ACPI EDID

2024-12-02T23:34:43+00:00

An HP Pavilion Aero Laptop 13-be0xxx/8916 has an ACPI EDID, but using
it is causing corruption. It's got illogical values of not specifying
a digital interface. Sanity check the ACPI EDID to avoid tripping such
problems.

Suggested-by: Tobias Jakobi 
Reported-and-tested-by: Chris Bainbridge 
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3782
Fixes: c6a837088bed ("drm/amd/display: Fetch the EDID from _DDC if available for eDP")
Reviewed-by: Harry Wentland 
Link: https://lore.kernel.org/r/20241128032500.2088288-1-superm1@kernel.org
Signed-off-by: Mario Limonciello 
Signed-off-by: Alex Deucher