drm/i915: do not stop engines on sanitize if i915.reset=0

Since commit 5896a5c8c9c0 (drm/i915: Always stop the rings before a
missing GPU reset) we attempt to stop the engines during gem_sanitize
even if reset=0 and nothing bad happened on the gpu.
The specs says that the STOP_RINGS bit needs to be cleared to resume
normal operation, but for some reason the value of the bit seems to be
changing without us writing to it (maybe rc6 entry/exit?), so normal
operation resumes correctly. However, it still feels incorrect to stop
the engines if there hasn't been any issue so skip the whole reset
call in gem_sanitize if i915.reset=0

Cc: Chris Wilson <[email protected]>
Cc: Mika Kuoppala <[email protected]>
Signed-off-by: Daniele Ceraolo Spurio <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Reviewed-by: Chris Wilson <[email protected]>
Signed-off-by: Chris Wilson <[email protected]>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 32883bb04747084df61e2d898c6b3446988aa517..021588950a528c8d9dd8bdca00f823a5aeeaea95 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4885,10 +4885,8 @@ void i915_gem_sanitize(struct drm_i915_private *i915)
         * it may impact the display and we are uncertain about the stability
         * of the reset, so this could be applied to even earlier gen.
         */
-       if (INTEL_GEN(i915) >= 5) {
-               int reset = intel_gpu_reset(i915, ALL_ENGINES);
-               WARN_ON(reset && reset != -ENODEV);
-       }
+       if (INTEL_GEN(i915) >= 5 && intel_has_gpu_reset(i915))
+               WARN_ON(intel_gpu_reset(i915, ALL_ENGINES));
 }
 
 int i915_gem_suspend(struct drm_i915_private *dev_priv)