[Intel-gfx] [PATCH] drm/i915/gt: Make sure that errors are propagated through request chains

[Matthew Auld]

On Fri, 10 Feb 2023 at 14:06, Andi Shyti <andi.shyti at linux.intel.com> wrote:
>
> Currently, for operations like memory clear or copy for big
> chunks of memory, we generate multiple requests executed in a
> chain.
>
> But if one of the requests generated fails we would not know it
> to unless it happens to the last request, because errors are not
> properly propagated.
>
> For this we need to keep propagating the chain of fence
> notification in order to always reach the final fence associated
> to the final request.
>
> This way we would know that the memory operation has failed and
> whether the memory is still invalid.
>
> On copy and clear migration signal fences upon completion.
>
> Fixes: cf586021642d80 ("drm/i915/gt: Pipelined page migration")
> Reported-by: Matthew Auld <matthew.auld at intel.com>
> Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
> Cc: stable at vger.kernel.org
Reviewed-by: Matthew Auld <matthew.auld at intel.com>