Commit 64f09f00 authored by Chris Wilson's avatar Chris Wilson

drm/i915: Clear lost context-switch interrupts across reset

During a global reset, we disable the irq. As we disable the irq, the
hardware may be raising a GT interrupt that we then ignore, leaving it
pending in the GTIIR. After the reset, we then re-enable the irq,
triggering the pending interrupt. However, that interrupt was for the
stale state from before the reset, and the contents of the CSB buffer
are now invalid.

v2: Add a comment to make it clear that the double clear is purely my
paranoia.
Reported-by: default avatar"Dong, Chuanxiao" <chuanxiao.dong@intel.com>
Fixes: 821ed7df ("drm/i915: Update reset path to fix incomplete requests")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: "Dong, Chuanxiao" <chuanxiao.dong@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170807121919.30165-1-chris@chris-wilson.co.uk
Link: https://patchwork.freedesktop.org/patch/msgid/20170818090509.5363-1-chris@chris-wilson.co.ukReviewed-by: default avatarMichel Thierry <michel.thierry@intel.com>
parent a42894eb
......@@ -1221,6 +1221,14 @@ static int intel_init_workaround_bb(struct intel_engine_cs *engine)
return ret;
}
static u8 gtiir[] = {
[RCS] = 0,
[BCS] = 0,
[VCS] = 1,
[VCS2] = 1,
[VECS] = 3,
};
static int gen8_init_common_ring(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
......@@ -1245,9 +1253,22 @@ static int gen8_init_common_ring(struct intel_engine_cs *engine)
DRM_DEBUG_DRIVER("Execlists enabled for %s\n", engine->name);
/* After a GPU reset, we may have requests to replay */
GEM_BUG_ON(engine->id >= ARRAY_SIZE(gtiir));
/*
* Clear any pending interrupt state.
*
* We do it twice out of paranoia that some of the IIR are double
* buffered, and if we only reset it once there may still be
* an interrupt pending.
*/
I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]),
GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift);
I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]),
GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift);
clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
/* After a GPU reset, we may have requests to replay */
submit = false;
for (n = 0; n < ARRAY_SIZE(engine->execlist_port); n++) {
if (!port_isset(&port[n]))
......
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