PR of Maira's pmdomain/downstream/timeouts branch#7400
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Commit 18605b1 ("pmdomain: bcm: bcm2835-power: Increase ASB control timeout") raised the ASB handshake polling budget from 1us to 5us. Surveying the pmdomain subsystem, 5us is still the smallest polling budget by a wide margin - comparable handshakes in other drivers use: - 100us : starfive jh71xx-pmu, apple pmgr-pwrstate - 1ms : renesas rcar-sysc, rmobile-sysc (power-on) - 10ms : renesas rcar-gen4-sysc, sunxi sun55i-pck600 - 1s : mediatek mtk-pm-domains, mtk-scpsys Raise the bcm2835 timeout to 500us, matching analogous drivers. 500us is still negligible relative to a power-domain transition and gives the V3D master ASB substantially more headroom to drain under heavy workloads, where 5us has been observed to be insufficient in practice. Cc: stable@vger.kernel.org Fixes: b826d2c ("pmdomain: bcm: bcm2835-power: Increase ASB control timeout") Signed-off-by: Maíra Canal <mcanal@igalia.com>
v3d_mmu_set_page_table() ends by calling v3d_mmu_flush_all() to flush the
MMU cache and clear the TLB after reprogramming V3D_MMU_PT_PA_BASE.
v3d_mmu_flush_all() is gated by pm_runtime_get_if_active(), which returns
0 unless runtime_status == RPM_ACTIVE.
v3d_mmu_set_page_table() is called from two paths that *know* V3D is
reachable, but where the runtime PM status is wrong:
1. v3d_power_resume(): the runtime resume callback itself, where
runtime_status is RPM_RESUMING.
2. v3d_reset(): called from the DRM scheduler timeout handler with the
hung job's pm_runtime reference held, so RPM_ACTIVE, but here we
don't need to take an extra reference for the duration of the flush
either.
In both cases pm_runtime_get_if_active() returns 0, the flush is silently
skipped, and V3D resumes executing with whatever MMUC/TLB state happened
to survive the last reset. On BCM2711, this leaves stale translations live
across runtime PM cycles, manifesting as random GPU hangs.
Split the actual flush sequence into a helper that does the writes
unconditionally, and have v3d_mmu_set_page_table() call it directly.
Fixes: 17af1d14deaf ("drm/v3d: Introduce Runtime Power Management")
Cc: stable@vger.kernel.org
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Maíra Canal <mcanal@igalia.com>
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Turn Maira's branch into a PR to get the build artefacts.