[Intel-gfx] [PATCH 1/3] drm/i915/ringbuffer: EMIT_INVALIDATE *before* switch context
Chris Wilson
chris at chris-wilson.co.uk
Mon Jan 28 21:52:46 UTC 2019
Despite what I think the prm recommends, commit f2253bd9859b
("drm/i915/ringbuffer: EMIT_INVALIDATE after switch context") turned out
to be a huge mistake when enabling Ironlake contexts as the GPU would
hang on either a MI_FLUSH or PIPE_CONTROL immediately following the
MI_SET_CONTEXT of an active mesa context (more vanilla contexts, e.g.
simple rendercopies with igt, do not suffer).
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/intel_ringbuffer.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index ee3719324e2d..db21606095d2 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1968,12 +1968,12 @@ static int ring_request_alloc(struct i915_request *request)
*/
request->reserved_space += LEGACY_REQUEST_SIZE;
- ret = switch_context(request);
+ /* Unconditionally invalidate GPU caches and TLBs. */
+ ret = request->engine->emit_flush(request, EMIT_INVALIDATE);
if (ret)
return ret;
- /* Unconditionally invalidate GPU caches and TLBs. */
- ret = request->engine->emit_flush(request, EMIT_INVALIDATE);
+ ret = switch_context(request);
if (ret)
return ret;
--
2.20.1
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