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i965: Properly return *RESET* status in glGetGraphicsResetStatusARB

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The glGetGraphicsResetStatusARB from ARB_robustness extension always
returns GUILTY_CONTEXT_RESET_ARB and never returns NO_ERROR for guilty
context with LOSE_CONTEXT_ON_RESET_ARB strategy.  This is because Mesa
returns GUILTY_CONTEXT_RESET_ARB if batch_active !=0 whereas kernel
driver never reset batch_active and this variable always > 0 for guilty
context.  The same behaviour also can be observed for batch_pending and
INNOCENT_CONTEXT_RESET_ARB.

But ARB_robustness spec says:

  If a reset status other than NO_ERROR is returned and subsequent calls
  return NO_ERROR, the context reset was encountered and completed. If a
  reset status is repeatedly returned, the context may be in the process
  of resetting.

  8. How should the application react to a reset context event?
  RESOLVED: For this extension, the application is expected to query the
  reset status until NO_ERROR is returned. If a reset is encountered, at
  least one *RESET* status will be returned. Once NO_ERROR is
  encountered, the application can safely destroy the old context and
  create a new one.

The main problem is the context may be in the process of resetting and
in this case a reset status should be repeatedly returned.  But looks
like the kernel driver returns nonzero active/pending only if the
context reset has already been encountered and completed.  For this
reason the *RESET* status cannot be repeatedly returned and should be
returned only once.

The reset_count and brw->reset_count variables can be used to control
that glGetGraphicsResetStatusARB returns *RESET* status only once for
each context.  Note the i915 triggers reset_count twice which allows to
return correct reset count immediately after active/pending have been
incremented.

v2 (idr): Trivial reformatting of comments.

Signed-off-by: Pavel Popov <pavel.e.popov@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Cc: "10.1 10.2" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit 8dc4a98c44)
This commit is contained in:
Pavel Popov 2014-05-16 12:00:02 +07:00 • committed by Ian Romanick
parent a31062fcb3
commit 9a8f12ae03
1 changed files with 13 additions and 5 deletions
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18
src/mesa/drivers/dri/i965/brw_reset.c
View file

@ -42,6 +42,13 @@ brw_get_graphics_reset_status(struct gl_context *ctx)
*/
assert(brw->hw_ctx != NULL);
/* A reset status other than NO_ERROR was returned last time. I915 returns
* nonzero active/pending only if reset has been encountered and completed.
* Return NO_ERROR from now on.
*/
if (brw->reset_count != 0)
return GL_NO_ERROR;
err = drm_intel_get_reset_stats(brw->hw_ctx, &reset_count, &active,
&pending);
if (err)
@ -50,18 +57,19 @@ brw_get_graphics_reset_status(struct gl_context *ctx)
/* A reset was observed while a batch from this context was executing.
* Assume that this context was at fault.
*/
if (active != 0)
if (active != 0) {
brw->reset_count = reset_count;
return GL_GUILTY_CONTEXT_RESET_ARB;
}
/* A reset was observed while a batch from this context was in progress,
* but the batch was not executing. In this case, assume that the context
* was not at fault.
*/
if (pending != 0)
if (pending != 0) {
brw->reset_count = reset_count;
return GL_INNOCENT_CONTEXT_RESET_ARB;
/* FINISHME: Should we report anything if reset_count > brw->reset_count?
*/
}
return GL_NO_ERROR;
}