[Intel-gfx] [PATCH] drm/i915: Reset request handling for gen8+

[Chris Wilson]

On Thu, Jun 18, 2015 at 12:51:40PM +0300, Mika Kuoppala wrote:
> In order for gen8+ hardware to guarantee that no context switch
> takes place during engine reset and that current context is properly
> saved, the driver needs to notify and query hw before commencing
> with reset.
> 
> There are gpu hangs where the engine gets so stuck that it never will
> report to be ready for reset. We could proceed with reset anyway, but
> with some hangs with skl, the forced gpu reset will result in a system
> hang. By inspecting the unreadiness for reset seems to correlate with
> the probable system hang.
> 
> We will only proceed with reset if all engines report that they
> are ready for reset. If root cause for system hang is found and
> can be worked around with another means, we can reconsider if
> we can reinstate full reset for unreadiness case.
> 
> v2: -EIO, Recovery, gen8 (Chris, Tomas, Daniel)
> v3: updated commit msg
> v4: timeout_ms, simpler error path (Chris)
> 
> References: https://bugs.freedesktop.org/show_bug.cgi?id=89959
> References: https://bugs.freedesktop.org/show_bug.cgi?id=90854
> Testcase: igt/gem_concurrent_blit --r prw-blt-overwrite-source-read-rcs-forked
> Testcase: igt/gem_concurrent_blit --r gtt-blt-overwrite-source-read-rcs-forked

Is this the new format for subtests?

I thought the form was
igt/gem_concurrent_blit/prw-blt-overwrite-source-read-rcs-forked

> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Tomas Elf <tomas.elf at intel.com>
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>

Lgtm,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre