drm/i915: Serialize per-engine resets against new requests
authorChris Wilson <chris@chris-wilson.co.uk>
Fri, 21 Jul 2017 12:32:21 +0000 (13:32 +0100)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Thu, 27 Jul 2017 07:38:44 +0000 (09:38 +0200)
commit0364cd19d61caad7292cc4e87f5001595b6c7642
tree37acce3360ee1b87d3e1789b39a8e54d4ece4da3
parentb4f3e1631f5e8fcfb1da84cbd5d3ec581480954a
drm/i915: Serialize per-engine resets against new requests

We rely on disabling the execlists (by stopping the tasklet) to prevent
new requests from submitting to the engine ELSP before we are ready.
However, we re-enable the engine before we call init_hw which gives
userspace the opportunity to subit a new request which is then
overwritten by init_hw -- but not before the HW may have started
executing. The subsequent out-of-order CSB is detected by our sanity
checks in intel_lrc_irq_handler().

Fixes: a1ef70e14453 ("drm/i915: Add support for per engine reset recovery")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170721123238.16428-3-chris@chris-wilson.co.uk
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/i915_drv.c