diff options
| author | Tim Chen <tim.c.chen@linux.intel.com> | 2026-09-21 17:37:22 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2026-09-22 10:49:53 +0200 |
| commit | 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 (patch) | |
| tree | 176dc2d685debcfb082c151ee94f2425ac96b364 /Documentation/gpu/intel-display | |
| download | linux-stable-0d6526f82c3cdefcca47f73f5fc08dc6f335eac6.tar.gz linux-stable-0d6526f82c3cdefcca47f73f5fc08dc6f335eac6.zip | |
sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling buggrafted
alb_break_llc() decides whether to break LLC preference during active
load balance. It does so by testing that every runnable fair task on the
source rq prefers its LLC:
env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable
But the two counters cover different sets. nr_pref_llc_running is updated
in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued,
so it follows queued tasks. h_nr_runnable is updated in set_delayed()/
clear_delayed() and drops delay-dequeued tasks.
So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted
in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks,
alb_break_llc() returns false, and active balance is free to pull a task
off its preferred LLC. Active balance only moves runnable tasks, and this
is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB
skips the per-task test in can_migrate_task(). The runnable set is the one
we want.
Fix it on the counter side. A task should be counted in
nr_pref_llc_running exactly while it is both queued on its preferred LLC
(pref_llc_queued) and runnable (!sched_delayed). Define that membership
once in task_pref_llc_runnable(), and adjust the counter only through
pref_llc_running_inc()/pref_llc_running_dec() from the four sites that
change either input: account_llc_enqueue(), account_llc_dequeue(),
set_delayed() and clear_delayed(). Gating every update on the same
predicate keeps the delay, wake and dequeue paths from double-counting
or underflowing; see the comments at those sites for the ordering.
nr_llc_running and sd->llc_counts are not touched and stay on queued
semantics.
Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC")
Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/
Reported-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kayra Cizmeci <kayracizmeci@gmail.com>
Cc: <stable@kernel.org> # v7.2.x
Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com
Diffstat (limited to 'Documentation/gpu/intel-display')
22 files changed, 295 insertions, 0 deletions
diff --git a/Documentation/gpu/intel-display/async-flip.rst b/Documentation/gpu/intel-display/async-flip.rst new file mode 100644 index 000000000..40f93e885 --- /dev/null +++ b/Documentation/gpu/intel-display/async-flip.rst @@ -0,0 +1,8 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Asynchronous Page Flip +====================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_display.c + :doc: asynchronous flip implementation diff --git a/Documentation/gpu/intel-display/atomic.rst b/Documentation/gpu/intel-display/atomic.rst new file mode 100644 index 000000000..43a473181 --- /dev/null +++ b/Documentation/gpu/intel-display/atomic.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Atomic Modeset Support +====================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_atomic.c + :doc: atomic modeset support + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_atomic.c + :internal: diff --git a/Documentation/gpu/intel-display/audio.rst b/Documentation/gpu/intel-display/audio.rst new file mode 100644 index 000000000..eef95df75 --- /dev/null +++ b/Documentation/gpu/intel-display/audio.rst @@ -0,0 +1,23 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +High Definition Audio +===================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_audio.c + :doc: High Definition Audio over HDMI and Display Port + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_audio.c + :internal: + +.. kernel-doc:: include/drm/intel/i915_component.h + :internal: + +Intel HDMI LPE Audio Support +============================ + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_lpe_audio.c + :doc: LPE Audio integration for HDMI or DP playback + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_lpe_audio.c + :internal: diff --git a/Documentation/gpu/intel-display/casf.rst b/Documentation/gpu/intel-display/casf.rst new file mode 100644 index 000000000..406778ccd --- /dev/null +++ b/Documentation/gpu/intel-display/casf.rst @@ -0,0 +1,8 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Content Adaptive Sharpness Filter (CASF) +======================================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_casf.c + :doc: Content Adaptive Sharpness Filter (CASF) diff --git a/Documentation/gpu/intel-display/cdclk.rst b/Documentation/gpu/intel-display/cdclk.rst new file mode 100644 index 000000000..a66d623b0 --- /dev/null +++ b/Documentation/gpu/intel-display/cdclk.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Display clocks +============== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c + :doc: CDCLK / RAWCLK + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cdclk.c + :internal: diff --git a/Documentation/gpu/intel-display/cmtg.rst b/Documentation/gpu/intel-display/cmtg.rst new file mode 100644 index 000000000..04edd0bd1 --- /dev/null +++ b/Documentation/gpu/intel-display/cmtg.rst @@ -0,0 +1,8 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Common Primary Timing Generator (CMTG) +====================================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_cmtg.c + :doc: Common Primary Timing Generator (CMTG) diff --git a/Documentation/gpu/intel-display/dmc.rst b/Documentation/gpu/intel-display/dmc.rst new file mode 100644 index 000000000..4368da4c7 --- /dev/null +++ b/Documentation/gpu/intel-display/dmc.rst @@ -0,0 +1,26 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +.. _drm/intel-display/dmc: + +DMC Firmware Support +==================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc.c + :doc: DMC Firmware Support + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc.c + :internal: + + +DMC Flip Queue +============== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_flipq.c + :doc: DMC Flip Queue + +DMC wakelock support +==================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dmc_wl.c + :doc: DMC wakelock support diff --git a/Documentation/gpu/intel-display/dp-link-capabilities.rst b/Documentation/gpu/intel-display/dp-link-capabilities.rst new file mode 100644 index 000000000..331cc69d1 --- /dev/null +++ b/Documentation/gpu/intel-display/dp-link-capabilities.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +DisplayPort Link Capabilities +============================= + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp_link_caps.c + :doc: DisplayPort link capabilities + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp_link_caps.h + :internal: diff --git a/Documentation/gpu/intel-display/dp-link-training.rst b/Documentation/gpu/intel-display/dp-link-training.rst new file mode 100644 index 000000000..d0bde9650 --- /dev/null +++ b/Documentation/gpu/intel-display/dp-link-training.rst @@ -0,0 +1,8 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +DisplayPort Link Training +========================= + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dp_link_training.c + :doc: DisplayPort link training diff --git a/Documentation/gpu/intel-display/dpio.rst b/Documentation/gpu/intel-display/dpio.rst new file mode 100644 index 000000000..84d92ac16 --- /dev/null +++ b/Documentation/gpu/intel-display/dpio.rst @@ -0,0 +1,8 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +DPIO +==== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpio_phy.c + :doc: DPIO diff --git a/Documentation/gpu/intel-display/dpll.rst b/Documentation/gpu/intel-display/dpll.rst new file mode 100644 index 000000000..c750352e0 --- /dev/null +++ b/Documentation/gpu/intel-display/dpll.rst @@ -0,0 +1,14 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Display PLLs +============ + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c + :doc: Display PLLs + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.c + :internal: + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.h + :internal: diff --git a/Documentation/gpu/intel-display/drrs.rst b/Documentation/gpu/intel-display/drrs.rst new file mode 100644 index 000000000..a5aaba63d --- /dev/null +++ b/Documentation/gpu/intel-display/drrs.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Display Refresh Rate Switching (DRRS) +===================================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_drrs.c + :doc: Display Refresh Rate Switching (DRRS) + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_drrs.c + :internal: diff --git a/Documentation/gpu/intel-display/dsb.rst b/Documentation/gpu/intel-display/dsb.rst new file mode 100644 index 000000000..857aca599 --- /dev/null +++ b/Documentation/gpu/intel-display/dsb.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Display State Buffer +==================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c + :doc: DSB + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c + :internal: diff --git a/Documentation/gpu/intel-display/fbc.rst b/Documentation/gpu/intel-display/fbc.rst new file mode 100644 index 000000000..de9e19021 --- /dev/null +++ b/Documentation/gpu/intel-display/fbc.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Frame Buffer Compression (FBC) +============================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fbc.c + :doc: Frame Buffer Compression (FBC) + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fbc.c + :internal: diff --git a/Documentation/gpu/intel-display/fifo-underrun.rst b/Documentation/gpu/intel-display/fifo-underrun.rst new file mode 100644 index 000000000..5d8f01921 --- /dev/null +++ b/Documentation/gpu/intel-display/fifo-underrun.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Display FIFO Underrun Reporting +=============================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fifo_underrun.c + :doc: fifo underrun handling + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_fifo_underrun.c + :internal: diff --git a/Documentation/gpu/intel-display/frontbuffer.rst b/Documentation/gpu/intel-display/frontbuffer.rst new file mode 100644 index 000000000..7ae38e082 --- /dev/null +++ b/Documentation/gpu/intel-display/frontbuffer.rst @@ -0,0 +1,14 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Frontbuffer Tracking +==================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_frontbuffer.c + :doc: frontbuffer tracking + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_frontbuffer.h + :internal: + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_frontbuffer.c + :internal: diff --git a/Documentation/gpu/intel-display/hotplug.rst b/Documentation/gpu/intel-display/hotplug.rst new file mode 100644 index 000000000..f33bc0087 --- /dev/null +++ b/Documentation/gpu/intel-display/hotplug.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Hotplug +======= + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_hotplug.c + :doc: Hotplug + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_hotplug.c + :internal: diff --git a/Documentation/gpu/intel-display/index.rst b/Documentation/gpu/intel-display/index.rst new file mode 100644 index 000000000..e81f49bf2 --- /dev/null +++ b/Documentation/gpu/intel-display/index.rst @@ -0,0 +1,46 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +.. _drm/intel-display: + +==================== +Intel Display Driver +==================== + +The Intel display driver provides the display, or :ref:`drm-kms`, support for +both the :ref:`drm/xe <drm/xe>` and :ref:`drm/i915 <drm/i915>` Intel GPU +drivers. + +The source code currently resides under ``drivers/gpu/drm/i915/display`` due to +historical reasons, and it's compiled separately into both drm/xe and drm/i915 +kernel modules. + +The drm/xe and drm/i915 drivers are the "core" or "parent" drivers for display, +as they initialize and own the drm device, and pass that on to the display +driver. The display driver isn't an independent driver in that sense. + +.. toctree:: + :maxdepth: 1 + :caption: Detailed display topics + + async-flip + atomic + audio + casf + cdclk + cmtg + dmc + dpio + dpll + drrs + dsb + fbc + fifo-underrun + frontbuffer + hotplug + dp-link-training + dp-link-capabilities + plane + psr + snps-phy + vbt diff --git a/Documentation/gpu/intel-display/plane.rst b/Documentation/gpu/intel-display/plane.rst new file mode 100644 index 000000000..59932a820 --- /dev/null +++ b/Documentation/gpu/intel-display/plane.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Atomic Plane Helpers +==================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_plane.c + :doc: atomic plane helpers + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_plane.c + :internal: diff --git a/Documentation/gpu/intel-display/psr.rst b/Documentation/gpu/intel-display/psr.rst new file mode 100644 index 000000000..63e56abcd --- /dev/null +++ b/Documentation/gpu/intel-display/psr.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Panel Self Refresh PSR (PSR/SRD) +================================ + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_psr.c + :doc: Panel Self Refresh (PSR/SRD) + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_psr.c + :internal: diff --git a/Documentation/gpu/intel-display/snps-phy.rst b/Documentation/gpu/intel-display/snps-phy.rst new file mode 100644 index 000000000..c9e333fa7 --- /dev/null +++ b/Documentation/gpu/intel-display/snps-phy.rst @@ -0,0 +1,8 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Synopsis PHY support +==================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_snps_phy.c + :doc: Synopsis PHY support diff --git a/Documentation/gpu/intel-display/vbt.rst b/Documentation/gpu/intel-display/vbt.rst new file mode 100644 index 000000000..be69f7fd7 --- /dev/null +++ b/Documentation/gpu/intel-display/vbt.rst @@ -0,0 +1,14 @@ +.. SPDX-License-Identifier: MIT +.. Copyright © 2026 Intel Corporation + +Video BIOS Table (VBT) +====================== + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c + :doc: Video BIOS Table (VBT) + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_bios.c + :internal: + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_vbt_defs.h + :internal: |