[Mesa-dev] [PATCH 4/4] i965: Drop the batch and limp along if execbuf fails.

[Chris Wilson]

Quoting Jason Ekstrand (2017-09-24 22:53:04)
> I've got this a few times recently and it's really annoying.  I don't know 
> if this will fix anything or not but it may be worth a go.  I fear, 
> however, that ignoring an execbuf failure will lead to permanently 
> corrupted rendering or even additional hangs due to a chunk of the stream 
> being missing.  That seems undesirable.  I would feel more comfortable 
> about if you flagged BRW_NEW_CONTEXT in this cases to force a full state 
> re-emit.

The other step to consider is dependency chains. If you replace the
batch with an empty one (just MI_BB_END) and execute it with the rest of
the execobjects, then all the fences (both implicit and explicit) will
be valid. Just the contents garbage, and gpu state can be fixed up by
NEW_CONTEXT as Jason suggested.
-Chris