We set out-of-bound parameters inside the i915_requests.flags field,
such as disabling preemption or marking the end-of-context. We should
not coalesce consecutive requests if they have differing instructions
as we only inspect the last active request in a context. Thus if we
allow a later request to be merged into the same execution context, it
will mask any of the earlier flags.
References: 2a98f4e65bba ("drm/i915: add infrastructure to hold off preemption
on a request")
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwer...@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwer...@intel.com>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c
b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 9666d51b7e97..7b43c1852776 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1184,6 +1184,9 @@ static bool can_merge_rq(const struct i915_request *prev,
if (i915_request_completed(next))
return true;
+ if (unlikely(prev->flags ^ next->flags) & I915_REQUEST_NOPREEMPT)
+ return false;
+
if (!can_merge_ctx(prev->hw_context, next->hw_context))
return false;
--
2.23.0
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