On 09/07/2024 15:02, Tvrtko Ursulin wrote:
On 09/07/2024 13:53, Nitin Gote wrote:
We're seeing a GPU HANG issue on a CHV platform, which was caused by
bac24f59f454 ("drm/i915/execlists: Enable coarse preemption boundaries
for gen8").
Gen8 platform has only timeslice and doesn't support a preemption
mechanism
as engines do not have a preemption timer and doesn't send an irq if the
preemption timeout expires. So, add a fix to not consider preemption
during dequeuing for gen8 platforms.
Also move can_preemt() above need_preempt() function to resolve implicit
declaration of function ‘can_preempt' error and make can_preempt()
function param as const to resolve error: passing argument 1 of
‘can_preempt’ discards ‘const’ qualifier from the pointer target type.
Fixes: bac24f59f454 ("drm/i915/execlists: Enable coarse preemption
boundaries for gen8")
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/11396
Suggested-by: Andi Shyti <andi.shyti@xxxxxxxxx>
Signed-off-by: Nitin Gote <nitin.r.gote@xxxxxxxxx>
Cc: Chris Wilson <chris.p.wilson@xxxxxxxxxxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx> # v5.2+
---
.../drm/i915/gt/intel_execlists_submission.c | 24 ++++++++++++-------
1 file changed, 15 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
index 21829439e686..30631cc690f2 100644
--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
@@ -294,11 +294,26 @@ static int virtual_prio(const struct
intel_engine_execlists *el)
return rb ? rb_entry(rb, struct ve_node, rb)->prio : INT_MIN;
}
+static bool can_preempt(const struct intel_engine_cs *engine)
+{
+ if (GRAPHICS_VER(engine->i915) > 8)
+ return true;
+
+ if (IS_CHERRYVIEW(engine->i915) || IS_BROADWELL(engine->i915))
+ return false;
+
+ /* GPGPU on bdw requires extra w/a; not implemented */
+ return engine->class != RENDER_CLASS;
Aren't BDW and CHV the only Gen8 platforms, in which case this function
can be simplifies as:
...
{
return GRAPHICS_VER(engine->i915) > 8;
}
?
+}
+
static bool need_preempt(const struct intel_engine_cs *engine,
const struct i915_request *rq)
{
int last_prio;
+ if ((GRAPHICS_VER(engine->i915) <= 8) && can_preempt(engine))
The GRAPHICS_VER check here looks redundant with the one inside
can_preempt().
One more thing - I think gen8_emit_bb_start() becomes dead code after
this and can be removed.
Regards,
Tvrtko
+ return false;
+
if (!intel_engine_has_semaphores(engine))
return false;
@@ -3313,15 +3328,6 @@ static void remove_from_engine(struct
i915_request *rq)
i915_request_notify_execute_cb_imm(rq);
}
-static bool can_preempt(struct intel_engine_cs *engine)
-{
- if (GRAPHICS_VER(engine->i915) > 8)
- return true;
-
- /* GPGPU on bdw requires extra w/a; not implemented */
- return engine->class != RENDER_CLASS;
-}
-
static void kick_execlists(const struct i915_request *rq, int prio)
{
struct intel_engine_cs *engine = rq->engine;
