Turns out some panels allow only AUX based backlight
by just setting the DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP and
not setting the DP_EDP_BACKLIGHT_AUX_ENABLE_CAP.
If we make DP_EDP_BACKLIGHT_AUX_ENABLE_CAP a necessity for AUX
based DPCD backlight these panels loose the ability to manipulate
backlight via AUX, especially ones with no PWM controller.
Remove this check from function so that panels who do not advertise
DP_EDP_BACKLIGHT_AUX_ENABLE_CAP but advertise
DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP are able to manipulate
backlight again.
Fixes: ed8be780bd ("drm/i915/backlight: Fix VESA backlight possible check condition")
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16507
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Michał Grzelak <michal.grzelak@intel.com>
Link: https://patch.msgid.link/20260716030959.436430-1-suraj.kandpal@intel.com
Double the fractional part of the horizontal scale factor
for the purposes of min_cdck calculation. This bumps the min
CDCLK sufficiently to overcome some kind of 2 PPC granularity
issue. Without this CDCLK may end up being too low and we get
underruns with certain horizontal downscale factors.
The current Bspec formula calls for doubling only the
fractional part below 0.5, and rounding it down to a
unit fraction. But that formula does not result in a
sufficient CDCLK bump in a lot of cases. Empirical evidence
supports doubling the entire fractional part, so let's just
do that while we wait for further analysis from the hardware
team.
Also note that the position of the scaler output window also
seems to matter. If the output is near the left edge of the
screen then lower CDCLK is sufficient, but moving the output
window further to the right causes underruns unless CDCLK is
also bumped. Some prefill happening during hblank already?
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260715120926.10786-5-ville.syrjala@linux.intel.com
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Tested-by: Vidya Srinivas <vidya.srinivas@intel.com>
Since commit 860e748bdd ("drm: ensure blend mode supported if pixel
format with alpha exposed"), drm_mode_config_validate() warns when a
plane exposes an alpha pixel format but not the "pixel blend mode"
property. The cursor (ARGB8888, all platforms) and the VLV/CHV primary
and sprite planes trip this.
Userspace has historically assumed premultiplied blending when the
property is not attached, so it is safe to assume that planes that
did not expose the property already blended with fixed pre-multiplied
alpha in hardware. Therefore, expose a "pixel blend mode" property
advertising only DRM_MODE_BLEND_PREMULTI to match that assumption and
silence the warning. The cursor call is unconditional; the primary and
sprite calls are gated to VLV/CHV, the only platforms whose format lists
include alpha formats.
Assisted-by: Claude:claude-opus-4-8
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Leandro Ribeiro <leandro.ribeiro@collabora.com>
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16623
Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20260715054221.451421-1-chaitanya.kumar.borah@intel.com
On Xe3+, the SoC can lower the fabric frequency when the display
needs less bandwidth than the minimum GV point. This threshold is
defined as 20 GB/s. The driver can choose to request this threshold
when the required data rate falls below it.
Add an extra QGV entry, with both peak bw and derated bw set to
20 GB/s, to the bandwidth info when all of the following hold:
1. The platform is Xe3+.
2. There is at least one existing QGV point.
3. The number of QGV points is below 8 (the maximum).
Once a plane group is found, the driver iterates over all QGV points
in that group to find the best match for the required data rate. If
the required data rate is below 20 GB/s, it selects the peak bw from
this new QGV point (20 GB/s).
v2: add the peak bandwidth threshold as an additional QGV entry
v3: drm_warn switched to drm_dbg_kms (Suraj)
Removed log in case of no sagv and some tweak in the log message
if the system has already the maximum number of QGV points
Bspec: 68880
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260615203355.218578-8-vinod.govindapillai@intel.com
Simplify the initialization of QGV points info by extracting
the code to initialize the QGV points info from dram info based
on the memory type. This will reduce the complexity of the init
QGV info routine as we will be supporting new memory types in
future platforms.
v2: rebase after Ville's refactoring
v3: patch description updated
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260615203355.218578-5-vinod.govindapillai@intel.com
Remove the fallback for VRAM to system memory, I tested it and that
doesn't work at all, only a black screen with pipe fault errors were
observed.
On systems with media GT, extra latency is added when accessing stolen
memory when the GT is in MC6. Since we additionally aren't counting how
much memory is used for stolen and we could in theory fill up the
entire stolen area with DPT's, avoid using stolen and only use the
default memory region.
Using stolen may also result in random system hangs under load.
Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/7513
Fixes: 775d0adc01 ("drm/xe/fbdev: Limit the usage of stolen for LNL+")
Cc: <stable@vger.kernel.org> # v6.12+
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patch.msgid.link/20260630135523.1775379-2-dev@lankhorst.se
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Acked-by: Matthew Brost <matthew.brost@intel.com> #teams
Inform the poor sop reading the logs why the initial FB was rejected
if there is no stolen memory.
Technically this should perhaps be an error since the plane is known
to be enabled at this point, and if there is no stolen then it clearly
can't be scanning out from anywhere. But maybe there are some
virtualization passthrough cases and whatnot where we might not be
able to get access to stolen, so keep it as debug (same as i915).
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260511214122.8468-9-ville.syrjala@linux.intel.com
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Acked-by: Matthew Brost <matthew.brost@intel.com> #teams
Properly turn off the plane if it is enabled but
.get_initial_plane_config() failed for whatever reason.
The hardware does (or at least did) perform some kind of automagic
plane disable when the pipe gets disabled, but we don't rely on that
anywhere else either. Also the GGTT/actual memory may get clobbered
afterwards, so leaving the plane enabled here could result in visual
corruption/GTT faults/etc.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260511214122.8468-2-ville.syrjala@linux.intel.com
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Commit 16df4cc63c ("drm/i915/display: Use ceiling division for NV12
UV surface offset calculation") computes the UV (chroma) surface
start/size as ceiling(half of Y plane start/size) directly from the
U16.16 fixed-point source rectangle:
x = fp_16_16_to_int_ceil(fp_16_16_div2(src.x1));
For a single pipe the source coordinates are integers, so this is
correct.
(UV start = ceiling(half of Y plane start)).
With bigjoiner + a plane scaler the picture changes. The pipe boundary
is a fixed integer destination pixel, but the plane's position and the
scaler ratio are arbitrary, so drm_rect_clip_scaled() maps the seam back
to a *fractional* per-pipe source. For a 1280->2407 upscaled NV12 plane
crossing the seam:
master src: width = 1204 * 1280/2407 = 640.265899, x1 = 0
joiner src: width = 1203 * 1280/2407 = 639.734115, x1 = 640.265884
The luma path floors this to an integer (src.x1 >> 16 = 640), but the
UV path takes ceiling(640.265884 / 2) = ceil(320.13) = 321. The Y plane
then starts at column 640 while the UV plane starts at 321*2 = 642,
pushing the chroma read one column past the 640-wide chroma surface on
the joiner secondary:
[CRTC:382:pipe C] PLANE ATS fault
[CRTC:382:pipe C][PLANE:267:plane 1C] fault (CTL=0x81009400, ...)
The spec "Y plane start" is the integer pixel the luma surface actually
programs (640), not the pre-floor fixed-point value (640.27). Convert
the Y plane start/size to integer first - matching skl_check_main_surface()
- and then apply the ceiling. This is a no-op for the integer (non-joiner)
case and yields the correct, in-bounds chroma offset for the fractional
joiner seam:
before fix after fix
master 1B: x=0 w=321 x=0 w=320 -> [0, 320)
slave 1C: x=321 w=320 x=320 w=320 -> [320, 640)
The two halves now tile the 640-wide chroma plane exactly and the ATS
fault is gone.
Assisted-by: GitHub-Copilot:Claude-Opus-4.8
Fixes: 16df4cc63c ("drm/i915/display: Use ceiling division for NV12 UV surface offset calculation")
Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patch.msgid.link/20260618181837.687302-1-vidya.srinivas@intel.com
Add KUnit tests for DP link fallback selection across eDP, SST, and MST.
Verify that the fallback logic properly selects the maximum allowed
configuration, iterates through allowed configurations, and disables
failed configs as expected.
These tests include UHBR vs. non-UHBR conditions, MST vs. SST mode,
and validate that subsequent fallback selections respect the updated
allowed configuration mask.
v2:
- Rebase on changes using a filter object instead of a mask of
configuration indices.
- Rebase on changes using an iteration object.
Reviewed-by: Michał Grzelak <michal.grzelak@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-35-imre.deak@intel.com
Add KUnit tests for link_caps updates shrinking or expanding the
supported rates and lane counts.
The tests also cover updates with disabled configurations, including
random shrink and expand sequences, to verify that disabled state,
allowed configurations, ordering, and max limits stay consistent across
updates.
v2: Remove test cases for the now unused merge update mode.
v3:
- Test config iteration in lane count, rate order as well.
- Keep space after comma in code comment. (Michał)
Reviewed-by: Michał Grzelak <michal.grzelak@intel.com> # v2
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260707124849.135319-4-imre.deak@intel.com
Add a simple baseline test for DP link caps iteration using a fixed
standard DP configuration table. This provides a minimal validity check,
independent of more complex test setups, verifying the iterator returns
expected configurations in ascending and descending order.
v2: Unchanged.
v3: Test config iteration in lane count, rate order as well.
Reviewed-by: Michał Grzelak <michal.grzelak@intel.com> # v2
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260707124849.135319-3-imre.deak@intel.com
Add a separate xe KUnit config for display tests.
The existing xe .kunitconfig builds xe statically, which is suitable for
non-display xe tests. The display code can only be enabled for xe when
xe is built as a module, so add a separate display config with DRM_XE=m
and DRM_XE_DISPLAY=y.
This can be folded back into the main xe KUnit config once the display
code becomes a separate module.
Reviewed-by: Michał Grzelak <michal.grzelak@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-29-imre.deak@intel.com
Disable the link configuration that failed training when selecting
fallback parameters.
Fallback still selects the next configuration using the existing
fallback order, but now also removes the failed configuration from the
allowed set. Functionally, this only affects the case where an MST <-> SST
mode switch occurs on the same root connector: previously, a configuration
that failed training in one mode could be reused in the other mode due
to the differing config iteration orders.
The current fallback logic also sets a temporary maximum link limit
across the allowed configurations to constrain subsequent modesets. This
legacy behavior is preserved for now; it will be removed once the
fallback logic relies solely on the individually disabled configurations
to restrict the allowed set.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-26-imre.deak@intel.com
The target maximum rate/lane count selected by the fallback logic may
exceed the current link_caps max_limits' rate/lane count, the latter of
which are used as a limit by the lookup functions when filtering allowed
configurations. To ensure the fallback search finds all relevant
candidates, temporarily reset the link_caps max_limits to the maximum
common supported capabilities.
After the fallback search completes, set the link_caps max_limits to the
configuration selected by the fallback logic, as before, determining
the allowed configurations for a subsequent modeset.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-24-imre.deak@intel.com
Remove the min/max rate and lane count fields from struct
link_config_limits after all state computation is converted to use the
configuration filter.
A simple min/max range cannot fully describe the valid configuration
set once individual configurations are disabled (for example by
fallback), as it may allow combinations that are not actually valid.
The configuration filter, on the other hand, always represents a
consistent set of valid configurations.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-23-imre.deak@intel.com
Use the link caps helper to select the maximum DP MST link configuration
for DSC computation, instead of using the separate max rate and lane
count limits, which may not form a valid configuration after individual
configs are disabled by fallback.
Also look up the maximum rate for state computation via the configuration
mask when checking the DSC hblank expansion quirk.
This is a step towards unifying configuration selection and iteration
across connector types and between compute and fallback paths.
The state computation should likely consider all allowed configurations,
as noted in the code comment; for now keep the existing DP MST DSC
behavior of selecting the maximum BW configuration determined by the MST
connector BW config iteration order.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-22-imre.deak@intel.com
Use the link caps helper to select the maximum MST link configuration
for non-DSC computation, instead of using the separate max rate and lane
count limits, which may not form a valid configuration after individual
configs are disabled by fallback.
This is a step towards unifying configuration selection and iteration
across connector types and between compute and fallback paths.
In some cases all configurations should be considered, as noted in the
code comment; for now keep the existing behavior of selecting the
maximum bandwidth configuration as determined by the MST connector's BW
config iteration order.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-21-imre.deak@intel.com
Use the link caps helper to select the maximum eDP link configuration
for DSC computation, instead of using the separate max rate and lane
count limits, which may not form a valid configuration after individual
configs are disabled by fallback.
This is a step towards unifying configuration selection and iteration
across connector types and between compute and fallback paths.
The state computation should likely consider all allowed configurations,
as noted in the code comment; for now keep the existing eDP DSC behavior
of selecting the maximum configuration determined by the eDP connector
rate / lane config iteration order.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-20-imre.deak@intel.com
Use the link caps configuration iterator for DP SST link configuration
computation for DSC mode. This is a step towards unifying configuration
selection and iteration across connector types and between compute and
fallback paths.
The iteration preserves the DP SST connector rate/lane ordering used by
the current code.
This also allows removing the now unused common rate count helper.
v2:
- Rebase on changes using a filter object instead of a mask of
configuration indices.
- Rebase on changes using an iteration object.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-19-imre.deak@intel.com
Use the link caps configuration iterator for DP SST link configuration
computation for non-DSC mode. This is a step towards unifying
configuration selection and iteration across connector types and between
compute and fallback paths.
The iteration preserves the DP SST connector rate/lane ordering used by
the current code.
This also allows removing the now unused common rate count helper.
v2:
- Rebase on changes using a filter object instead of a mask of
configuration indices.
- Rebase on changes using an iteration object.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-18-imre.deak@intel.com
Use the link caps configuration mask when applying DP compliance test
link parameters during state computation.
Preserve the legacy behavior of falling back to all configurations with
the requested lane count if the requested rate and lane count pair is
not allowed.
In case no valid configuration is found fail the modeset.
v2:
- Rebase on changes using a filter object instead of a mask of
configuration indices.
- Rebase on changes using an iteration object.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-17-imre.deak@intel.com
Query the maximum link BW configuration via the link caps interface to
compute the available TBT bandwidth. Unlike the max common link params
used so far for this, the max BW config also accounts for any forced
link parameters.
This makes the max BW link config query uniform across mode validation
and TBT BW calculation, and allows unexporting the
intel_dp_link_caps_max_common_lane_count() helper.
v2: Use the max BW link configuration, instead of the max link limits.
Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-16-imre.deak@intel.com
