From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 8 Aug 2018 10:51:00 +0000 (+0100)
Subject: drm/i915: Unmask user interrupts writes into HWSP on snb/ivb/vlv/hsw
X-Git-Tag: for-linus-4.19b-rc1b-tag~29^2^2~4
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=341a15bb91d478c33d97b3b452a55181e5db6ea6;p=users%2Fdwmw2%2Flinux.git
drm/i915: Unmask user interrupts writes into HWSP on snb/ivb/vlv/hsw
An oddity occurs on Sandybridge, Ivybridge and Haswell (and presumably
Valleyview) in that for the period following the GPU restart after a
reset, there are no GT interrupts received. From Ville's notes, bit 0 in
the HWSTAM corresponds to the render interrupt, and if we unmask it we
do see immediate resumption of GT interrupt delivery (via the master irq
handler) after the reset.
v2: Limit the w/a to the render interrupt from rcs
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107500
Fixes: c5498089463b ("drm/i915: Mask everything in ring HWSTAM on gen6+ in ringbuffer mode")
References: d420a50c21ef ("drm/i915: Clean up the HWSTAM mess")
Testcase: igt/gem_eio/reset-stress
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180808105101.913-2-chris@chris-wilson.co.uk
(cherry picked from commit a4a717010f4e8cacaa3f0cae8a22f25c39ae1d41)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 33faad3197fee..6a8f27d0a7429 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -387,8 +387,18 @@ static void intel_ring_setup_status_page(struct intel_engine_cs *engine)
mmio = RING_HWS_PGA(engine->mmio_base);
}
- if (INTEL_GEN(dev_priv) >= 6)
- I915_WRITE(RING_HWSTAM(engine->mmio_base), 0xffffffff);
+ if (INTEL_GEN(dev_priv) >= 6) {
+ u32 mask = ~0u;
+
+ /*
+ * Keep the render interrupt unmasked as this papers over
+ * lost interrupts following a reset.
+ */
+ if (engine->id == RCS)
+ mask &= ~BIT(0);
+
+ I915_WRITE(RING_HWSTAM(engine->mmio_base), mask);
+ }
I915_WRITE(mmio, engine->status_page.ggtt_offset);
POSTING_READ(mmio);