On Tue, Sep 22, 2026 at 11:46:31AM -0300, Tales A. Mendonça wrote: Thanks for the patches, I've merge to drm-xe-next.
Matt > Hi, > > v6 of the TLB invalidation ack stall fix for ARL. Tracked in: > > https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/8678 > > The whole series now carries Matthew Brost's Reviewed-by - thank you for > working through it, including cross-checking patch 3 against the i915 > implementation. > > Recap: on the standalone media GT of MTL/ARL the CPU reads stale cache > lines for data the GuC has already written. The visible symptom is TLB > invalidation acks appearing to stall for a near-constant ~2.3s. i915 > works around this as Wa_22016122933; xe never inherited it. Patch 3 > implements it, applying XE_BO_FLAG_NEEDS_UC to the GuC-shared > allocations (CTBs, log, ADS, SLPC, engine activity) on the standalone > media GT, scoped by a new OOB rule (22016122933 MEDIA_VERSION(1300)). > > The one code change since v5 is in patch 1, from a second issue Sashiko > raised: the capture could run without a runtime PM reference. Every > pending invalidation fence holds one, taken in > xe_tlb_inval_fence_init(), and xe_tlb_inval_fence_signal() drops it via > xe_tlb_inval_fence_fini(). The timeout loop signals the expired fences > and only then calls xe_devcoredump_gt(), whose forcewake acquisition has > always relied on the caller holding a PM reference. If those were the > last references the device could begin autosuspending before the > snapshot touched the hardware. v6 takes a reference while the pending > fences still guarantee the device is awake, and releases it after the > capture. Matt confirmed the analysis and the fix on the list. > > I am carrying Matt's tag on patch 1 across that change since he reviewed > the fix itself, but flagging it here so it is not silently inherited. > > Two open points from earlier revisions, both now settled: > > - LRC coverage: i915 also marks the LRC UC on non-dGPU > (__lrc_alloc_state()). That does not match the erratum's direction - > LRC writes come from hardware context save and the GuC reads it - > and Matt's guidance was to leave i915 alone and treat it as out of > scope for xe. > > - SIGID: the TLB logging in patch 2 will be converted once a TLB > component exists in DEFINE_XE_LOG_COMPONENTS(); a colleague of > Matt's volunteered to do that as a follow-up on top of this series. > > Two notes carried over, still open to either answer: > > 1. CPU mapping: keeping XE_BO_FLAG_NEEDS_UC (uncached on both sides). > It is the tested configuration and no throughput difference against > the CPU-WC variant was measurable. Matching i915's exact CPU-WC + > GGTT-UC combination needs either a new BO flag or decoupling the > GGTT cache-mode selection from XE_BO_FLAG_NEEDS_UC; happy to add > that plumbing if parity is preferred. > > 2. Fixes:/Cc: stable are left out, since MTL/ARL is require_force_probe > in xe. Also happy to add them. > > Validation of patch 3 is six weeks on two ARL machines (7d51 and 7dd1), > across kernels 7.1.6, 7.1.8 and 7.2, with over 10M TLB invalidations > processed and zero ack stalls. Before the fix both machines reproduced > 20-60 stalls/day, every day, on two GuC firmware versions. The 7dd1 > machine, which could not survive a day of media workloads on xe without > a platform freeze, has been running xe full time since 11 August with > zero incidents. > > checkpatch is clean, except for one --strict CHECK about macro argument > reuse in the xe_devcoredump() wrapper in patch 1, which is intentional: > the macro only exists to forward (_q)->gt alongside _q. > > v5 -> v6: > - Rebased on today's drm-tip; builds clean, no conflicts. > - Patch 1: hold a runtime PM reference across the devcoredump capture > (second issue reported by Sashiko, confirmed by Matt). > - Patches 1-3: collected Reviewed-by from Matthew Brost. > - Patches 2-3: otherwise unchanged. > > Thanks, > Tales > > Tales A. Mendonça (3): > drm/xe: Capture devcoredump on TLB invalidation timeout > drm/xe: Log when a timed out TLB invalidation ack finally arrives > drm/xe: Implement Wa_22016122933 > > drivers/gpu/drm/xe/xe_devcoredump.c | 46 ++++++++++-------- > drivers/gpu/drm/xe/xe_devcoredump.h | 15 ++++-- > drivers/gpu/drm/xe/xe_guc.c | 16 ++++++ > drivers/gpu/drm/xe/xe_guc.h | 2 + > drivers/gpu/drm/xe/xe_guc_ads.c | 3 +- > drivers/gpu/drm/xe/xe_guc_ct.c | 6 ++- > drivers/gpu/drm/xe/xe_guc_engine_activity.c | 6 ++- > drivers/gpu/drm/xe/xe_guc_log.c | 7 ++- > drivers/gpu/drm/xe/xe_guc_pc.c | 3 +- > drivers/gpu/drm/xe/xe_tlb_inval.c | 54 +++++++++++++++++++++ > drivers/gpu/drm/xe/xe_tlb_inval_types.h | 17 +++++++ > drivers/gpu/drm/xe/xe_wa_oob.rules | 1 + > 12 files changed, 143 insertions(+), 33 deletions(-) > > -- > 2.55.0 >
