drm/v3d: Use raw seqcount helpers instead of fighting with lockdep

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The `v3d_stats` sequence counter uses regular seqcount helpers, which
carry lockdep annotations that expect a consistent IRQ context between
all writers. However, lockdep is unable to detect that v3d's readers
are never in IRQ or softirq context, and that for CPU job queues, even
the write side never is. This led to false positive that were previously
worked around by conditionally disabling local IRQs under
IS_ENABLED(CONFIG_LOCKDEP).

Switch to the raw seqcount helpers which skip lockdep tracking entirely.
This is safe because jobs are fully serialized per queue: the next job
can only be queued after the previous one has been signaled, so there is
no scope for the start and update paths to race on the same seqcount.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Link: https://patch.msgid.link/20260306-v3d-reset-locking-improv-v3-2-49864fe00692@igalia.com
Co-developed-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Maíra Canal <mcanal@igalia.com>

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Tvrtko Ursulin 2026-03-06 08:30:34 -03:00 • committed by Maíra Canal

parent 8cf1bec37b

commit 0b2a4569cd

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3 changed files with 17 additions and 46 deletions

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2

drivers/gpu/drm/v3d/v3d_drv.c

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5

drivers/gpu/drm/v3d/v3d_drv.h

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54

drivers/gpu/drm/v3d/v3d_sched.c

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