Commit fdd9b7dc authored Mar 27, 2023 by Matt Roper Committed by Andi Shyti Mar 28, 2023

drm/i915: Check for unreliable MMIO during forcewake

Although we now sanitycheck MMIO access during driver load to make sure
the MMIO BAR isn't returning all 0xFFFFFFFF, there have been a few cases
where (temporarily?) unreliable MMIO access has happened after GPU
resets or power events. We'll often notice this on our next GT register
access since forcewake handling will fail; let's change our handling
slightly so that when this happens we print a more meaningful message
clarifying that the problem is the MMIO access, not forcewake
specifically.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230327195547.356584-3-andi.shyti@linux.intel.com

parent de414973

drivers/gpu/drm/i915/intel_uncore.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -178,13 +178,20 @@ wait_ack_set(const struct intel_uncore_forcewake_domain *d,
		static inline void
		fw_domain_wait_ack_clear(const struct intel_uncore_forcewake_domain *d)
		{
		if (wait_ack_clear(d, FORCEWAKE_KERNEL)) {
		if (!wait_ack_clear(d, FORCEWAKE_KERNEL))
		return;

		if (fw_ack(d) == ~0)
		drm_err(&d->uncore->i915->drm,
		"%s: MMIO unreliable (forcewake register returns 0xFFFFFFFF)!\n",
		intel_uncore_forcewake_domain_to_str(d->id));
		else
		drm_err(&d->uncore->i915->drm,
		"%s: timed out waiting for forcewake ack to clear.\n",
		intel_uncore_forcewake_domain_to_str(d->id));

		add_taint_for_CI(d->uncore->i915, TAINT_WARN); /* CI now unreliable */
		}
		}

		enum ack_type {
		ACK_CLEAR = 0,