Introduce the main part of the new fb_pin parent interface:
- intel_parent_fb_pin_ggtt_(un)pin()
- intel_parent_fb_pin_dpt_(un)pin()
- intel_parent_fb_pin_reuse_vma()
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-14-ville.syrjala@linux.intel.com
Restructure reuse_vma() into a form that doesn't need the plane
state structs, and rename the result to xe_fb_pin_reuse_vma().
This will become the new fb_pin parent interface.
v2: Fix memcmp() arguments
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-13-ville.syrjala@linux.intel.com
Extract the inner DPT parts of intel_plane_(un)pin() into the
xe_fb_pin_ggtt_(un)pin(). These will become part of the new
fb_pin parent interface.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-12-ville.syrjala@linux.intel.com
Extract the inner DPT parts of intel_plane_(un)pin() into the
xe_fb_pin_dpt_(un)pin(). These will become part of the new
fb_pin parent interface.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-11-ville.syrjala@linux.intel.com
Move most of the plane state stuff out from the inner parts
of intel_plane_pin_fb(). The plan is to take those inner parts and
abstract them into the new fb_pin parent interface, and we don't
want any plane_state stuff there.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-10-ville.syrjala@linux.intel.com
This fbdev vma reuse hacks is a massive layering violation. It
really does not belong in the fb pinning code. And it's in the
way of properly abstracting this stuff, so kill it.
I don't think this hack even does anything useful because the
normal view will just use bo->ggtt_node when present, and the
fbdev bo will be permanenly pinned with xe_bo_create_pin_map_at_novm()
which does set up bo->ggtt_node. So we should never end up
rebuilding the PTEs for the fbdev bo, even without the reuse hack.
v2: Pimp the commit message a a bit (Jani)
v3: Also nuke intel_fbdev_vma_pointer()
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-9-ville.syrjala@linux.intel.com
No need to bother the higher level pinning code with the
FORCE_WC assert. Move it into the lower level function.
This also introduces the check to intel_fb_pin_to_ggtt(), which
(for the moment) is still used for the fbdev bo setup. But this
is all display stuff we're talking about here so having the check
is correct everywhere.
v2: Pimp the commit message a bit (Jani)
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-8-ville.syrjala@linux.intel.com
Extract the inner DPT parts of intel_plane_(un)pin() into the
i915_fb_pin_ggtt_(un)pin(). These will become part of the new
fb_pin parent interface.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-7-ville.syrjala@linux.intel.com
Extract the inner DPT parts of intel_plane_(un)pin() into the
i915_fb_pin_dpt_(un)pin(). These will become part of the new
fb_pin parent interface.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-6-ville.syrjala@linux.intel.com
Move most of the plane state stuff out from the inner parts
of intel_plane_pin_fb(). The plan is to take those inner parts and
abstract them into the new fb_pin parent interface, and we don't
want any plane_state stuff there.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-5-ville.syrjala@linux.intel.com
Move the i915_dpt_offset() check into the lower level
intel_fb_pin_to_dpt() function. Clears out some of the unnecessary
junk from the higher level code, making it easier to introduce
the new fb_pin parent interface.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-4-ville.syrjala@linux.intel.com
strut intel_fb_pin_params will be an important part of the fb_pin
interface, so move the definition to the parent interface file.
Or maybe we should have a separate header for this kind of stuff
since the users of the parent interface will need the struct
definition but not the parent interface vfunc struct definitions?
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-3-ville.syrjala@linux.intel.com
Introduce the "fb_pin" parent interface, as the first trivial step
move the *_get_map() stuff there.
The whole "fb_pin" as an interface might not really make sense,
and perhaps this (and other stuff) should just be collected into
some kind of "bo" interface. But let's go with "fb_pin" for now
to match where things are implemented, and possibly restructure
it later.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260508143426.26504-2-ville.syrjala@linux.intel.com
Prefer to use === instead of --- for top level section heading
underlines to allow using the latter for sub-headings later.
While at it, fix the underline lenghts where needed.
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/f49968792220ca3ff24efde813550850340d092e.1778235406.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Nowadays, the display support for drm/i915 and drm/xe is shared between
the drivers, even though the code is located under drm/i915/display.
The drm/i915 documentation has everything, including display topics, in
one huge page, while the drm/xe documentation is well-organized but
hardly mentions display. It's not great, to put it mildly.
Split out the Intel display documentation to a dedicated directory,
Documentation/gpu/intel-display. Also directly split the
functionality/feature documentation to dedicated pages to keep the main
index page high level and readable. We'll want to organize this further,
but just sort them alphabetically for starters.
Drop the boilerplate documentation sections that don't actually document
anything.
Cross-reference drm/i915, drm/xe, and intel-display.
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/21bfa7777eb0926eadd309d4c6f5c9cf48405cf0.1778235406.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Fix the error path during DDI encoder/connector initialization by
calling the missing TC port cleanup function.
This fixes the leaked TC port state.
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260507065940.2046690-1-imre.deak@intel.com
At the moment, in intel_dp_compute_config(), intel_panel_fixed_mode() is
called to check if the panel has any fixed mode or not. If it is an eDP
and has the fixed mode, then intel_panel_compute_config() is called.
However, the intel_panel_compute_config already checks if the panel
supports a fixed mode and returns early if it doesn't. This makes the
earlier check in the caller redundant.
Remove this extra check for intel_panel_fixed_mode().
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260430131220.3891497-6-ankit.k.nautiyal@intel.com
Currently, in intel_sdvo_compute_config(), intel_panel_fixed_mode() is
called to get the fixed mode. However, since the call is made after
intel_panel_compute_config, that copies the selected fixed mode to the
adjusted mode, we can directly use the crtc_state->hw.adjusted_mode.
So remove the extra call to intel_panel_fixed_mode() and use adjusted
mode instead.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260430131220.3891497-5-ankit.k.nautiyal@intel.com
The function intel_dvo_compute_config() calls intel_panel_fixed_mode() only
to check if there is a valid fixed_mode and based on that it then calls
intel_panel_compute_config().
However, since the intel_panel_compute_config() already checks for
fixed_mode and we can drop the call to intel_panel_fixed_mode().
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260430131220.3891497-4-ankit.k.nautiyal@intel.com
Currently, most callers of intel_panel_mode_valid() also call
intel_panel_fixed_mode(). This is done either to check for the presence of
a fixed mode for the connector or to get the clock of the fixed mode, which
is then compared against the max dotclock for the pipe.
Since intel_panel_mode_valid() already calls intel_panel_fixed_mode()
internally, we can avoid yet another call to intel_panel_fixed_mode() from
the caller.
Remove the redundant call to intel_panel_fixed_mode() in mode_valid paths.
To get the clock for the fixed mode, extend the helper
intel_panel_mode_valid() to accept 'target_clock' as an out param.
The 'target_clock' can then be used by the callers to check against the
max dotclock.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260430131220.3891497-3-ankit.k.nautiyal@intel.com
For LVDS SDVO, mode validation checks the requested mode against the
pipe max dotclock, but does not validate the selected fixed mode clock.
After intel_panel_mode_valid(), get the fixed mode and validate its
clock against the max dotclock.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260430131220.3891497-2-ankit.k.nautiyal@intel.com
intel_hdcp_required_content_stream() walks every connector on the
digital port to populate hdcp_port_data->streams[]. The only filter is
connector_status_disconnected, which reflects physical presence on the
MST topology, not whether the connector currently drives a stream.
On a multi-sink MST setup where only a subset of sinks are modeset,
the loop can pick a sibling MST connector that is connected but has
no active CRTC / VC payload. intel_conn_to_vcpi() then logs "MST
Payload not present" and returns 0, and the bogus StreamID=0 is
written to the repeater in RepeaterAuth_Stream_Manage (DPCD 0x693F0).
Authentication completes, but the repeater shortly raises
LINK_INTEGRITY_FAILURE (RxStatus 0x69493 bit4) because the StreamID
does not match any stream on its input. The HDCP check work then
tears the link down, the Content Protection property drops back to
DESIRED, and userspace observes a spurious HDCP enable failure.
Filter the connector iteration to only those with a CRTC assigned in
the new atomic state, so intel_conn_to_vcpi() is called for the
connector actually being enabled and reads its real VCPI from the MST
topology state.
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Santhosh Reddy Guddati <santhosh.reddy.guddati@intel.com>
Link: https://patch.msgid.link/20260505094022.4064256-1-suraj.kandpal@intel.com
Fix __xe_pin_fb_vma_ggtt() to actually respect the GGTT alignment
specified by the display code. Misalignment can cause GTT faults
etc.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260430154602.11393-2-ville.syrjala@linux.intel.com
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Instead of just looking at the first plane use the fb cached overall
minimum alignment.
This aligns with how the i915 version of intel_plane_pin_fb works.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
[vsyrjala: Rebase due to pin_params]
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260430154602.11393-1-ville.syrjala@linux.intel.com
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
This reverts commit 025f89b01e.
025f89b01e ("drm/i915: replace select with dependency for visible
DEBUG_OBJECTS") breaks the build in certain scenarios, presumably
because config DRM_I915_DEBUG selects DRM_I915_SW_FENCE_DEBUG_OBJECTS
without looking at its dependencies, allowing
DRM_I915_SW_FENCE_DEBUG_OBJECTS=y and DEBUG_OBJECTS=n.
Fixes: 025f89b01e ("drm/i915: replace select with dependency for visible DEBUG_OBJECTS")
Cc: Julian Braha <julianbraha@gmail.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Link: https://patch.msgid.link/20260506101957.202271-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
DRM_I915_SW_FENCE_DEBUG_OBJECTS currently selects DEBUG_OBJECTS even though
DEBUG_OBJECTS is visible to users. Other config options use 'depends on'
for DEBUG_OBJECTS, so let's do the same here.
This select-visible Kconfig misusage was detected by Kconfirm, a static
analysis tool for Kconfig.
Signed-off-by: Julian Braha <julianbraha@gmail.com>
Link: https://patch.msgid.link/20260502191932.4491-1-julianbraha@gmail.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
intel_pch_init_clock_gating() already handles unsupported PCH types,
including PCH_NOP, by doing nothing.
Drop the explicit HAS_PCH_NOP() check from the IVB clock gating
path and always call the display helper directly. This removes one
more direct dependency on display-side PCH macros from
intel_clock_gating.c.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-9-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Move the remaining pre-HSW display clock gating programming into
display.
This also drops display register includes from intel_clock_gating.c.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-8-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Move the HSW and BDW display clock gating programming into the display
code. In this case we need two different helpers, because the common
code between these two is split in the middle.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-7-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Move the GLK-specific display clock gating programming into display
intel_display_clock_gating.c, to remove more dependencies from i915 to
display registers.
Now that all remaining Gen9-family callers moved into display, we can
move the shared Gen9 display clock gating helper into display and
remove the old local helper from intel_clock_gating.c.
Additionally, the SKL_DE_COMPRESSED_HASH_MODE programming was
protected by HAS_LLC(), but that's incidental, because in Gen9
platforms, only SKL and KBL, for which this workaround applies, have
LLC(). In order not to use HAS_LLC() in display code, we can simply
remove this check from the generic Gen9 function and move the
SKL_DE_COMPRESSED_HASH_MODE programming to the KBL and SKL specific
functions. And, intentionally or not, CFL and CML were also using
this workaround, because they also have LLC, even though the comments
were only mentioning SKL and KBL. In order not to change anything
functionally with this patch, the workaround was also added to
intel_display_cfl_init_clock_gating().
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-6-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Move the BXT-specific display clock gating programming into display
intel_display_clock_gating.c, to remove more dependencies from i915.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-5-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Move the CFL/CML-specific display clock gating programming into
display intel_display_clock_gating.c, to remove more dependencies from
i915 to display registers.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-4-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Move the KBL-specific display clock gating programming into a
display intel_display_clock_gating.c, to remove more dependencies from
i915 to display registers.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-3-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Move the SKL-specific display clock gating programming into a new file
inside display.
This removes dependency from intel_clock_gating.c to the display's
intel_pch.h file, so we can remove the include statement.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260428095104.818360-2-luciano.coelho@intel.com
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Now that intel_conn_to_vcpi() reads the MST topology state via
drm_atomic_get_new_mst_topology_state(), the topology state belongs
to this atomic commit and is already serialized through the atomic
state's private object machinery. There is no need to additionally
take mgr->base.lock here.
Taking it from the HDCP enable path in commit_tail with
state->base.acquire_ctx is also unsafe: by this point the
acquire_ctx is no longer in a state where new modeset locks may be
acquired through it, which produces a modeset-lock splat on MST +
HDCP. Drop the drm_modeset_lock() call.
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Tested-by: Santhosh Reddy Guddati <santhosh.reddy.guddati@intel.com>
Reviewed-by: Santhosh Reddy Guddati <santhosh.reddy.guddati@intel.com>
Link: https://patch.msgid.link/20260504101117.3619984-3-suraj.kandpal@intel.com
intel_conn_to_vcpi() runs from the HDCP enable path in commit_tail
and looks up the VCPI via mgr->base.state. When an ALLOCATE_PAYLOAD
is being driven on the mgr just before HDCP enable, that payload
list is being mutated in place, so the lookup can miss the port and
trip drm_WARN_ON(!payload), causing HDCP to be programmed with
VCPI 0.
Use drm_atomic_get_new_mst_topology_state() to read the topology
state attached to this atomic commit (stable, decided in
atomic_check), and bail out cleanly when no topology state or
payload is present for this port instead of WARNing.
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Tested-by: Santhosh Reddy Guddati <santhosh.reddy.guddati@intel.com>
Reviewed-by: Santhosh Reddy Guddati <santhosh.reddy.guddati@intel.com>
Link: https://patch.msgid.link/20260504101117.3619984-2-suraj.kandpal@intel.com
Move generic crtc-ish modeset related functions under a new modeset
sub-struct of struct intel_display. Rename struct intel_display_funcs to
intel_modeset_funcs to make it a little bit more specific. Remove the
funcs sub-struct.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/7849de3a5c9755639c179917c6a298de9ac832c0.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Move cdclk related functions under cdclk sub-struct of struct
intel_display.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/a3cadca7cfd03486404af497fa62efb8e2d2adcd.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Move dpll related functions under dpll sub-struct of struct
intel_display.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/02efd924d7efdf42655f5c9bfd0f79a6df5fe2b4.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Move hotplug irq related functions under hotplug sub-struct of struct
intel_display.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/9419cff5038d60a6c95c247b83f54b6559067e0d.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Move watermark related functions under wm sub-struct of struct
intel_display.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/6b74ab66692dce20b2a6a8cb8cfdef222b2983ca.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Move fdi related functions under fdi sub-struct of struct intel_display.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/c48bad63ec94259773d05ef056268b02e119d635.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Move color related functions under color sub-struct of struct
intel_display.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/77cc5dd365f3346c4cbbe7a5d883bca413138c94.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Move audio related functions under audio sub-struct of struct
intel_display.
The funcs sub-struct of struct intel_display seems unnecessary. Instead
of display->funcs.FEATURE, prefer display->FEATURE.funcs.
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patch.msgid.link/60d626286b77c2faa9ff0518855dd083906b24be.1777537663.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
When a CRTC is moved to a different transcoder (e.g. on DP-MST stream
allocation), PIPE_SCANLINE and PIPE_FRMCNT can return values latched
from the previous transcoder/mode for up to one vblank period after
the new pipe is enabled. The vblank evasion code in
intel_pipe_update_start()/end() then samples a stale or boundary
scanline and the frame counter ticks during the critical section,
producing diagnostic errors of the form:
[243.348405] xe 0000:00:02.0: [drm] *ERROR* Atomic update failure on
pipe B (start=300 end=301) time 61 us, min 2128, max 2161, scanline
start 1200, end 2165
[248.536260] xe 0000:00:02.0: [drm] *ERROR* Atomic update failure on
pipe B (start=561 end=562) time 61 us, min 2128, max 2161, scanline
start 2162, end 2167
Here "scanline start 1200" is the vblank_start of a previously
programmed mode on a different transcoder, while "2162" is the current
mode's vblank_start sampled before any real frame has been emitted.
Both indicate a stale read rather than a real evasion miss.
Wait for one vblank after crtc_enable() to give the new transcoder a
chance to start producing live PIPE_SCANLINE/FRMCNT values before any
subsequent atomic commit enters the vblank evasion section. This adds
at most one frame of latency on modeset, which is invisible to users.
Reproduced with igt@kms_rotation_crc@sprite-rotation-180 on a DP-MST
sink; with this patch the failures no longer occur.
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Pranay Samala <pranay.samala@intel.com>
Link: https://patch.msgid.link/20260429042650.3335718-1-suraj.kandpal@intel.com
