[Intel-gfx] [PATCH i-g-t] tests/gem_reset_stats : mask off ring_stop bits

[Daniel Vetter]

On Wed, Jun 03, 2015 at 09:29:34AM +0100, Chris Wilson wrote:
> On Wed, Jun 03, 2015 at 09:20:21AM +0100, tim.gore at intel.com wrote:
> > From: Tim Gore <tim.gore at intel.com>
> > 
> > Function check_gpu_ok checks to make sure that any hangs
> > have cleared by testing for (flags == 0). Some tests set
> > the STOP_RINGS_ALLOW_BAN and STOP_RINGS_ALLOW_ERRORS flags
> > but these do not get cleared by an individual ring reset,
> > (a feature added recently to the driver), leading the
> > check_gpu_ok function to think that the gpu is still hung.
> > 
> > So I mask the flags with STOP_RING_ALL, to ignore the mode
> > bits and look only at the bits that stop the rings.
> > 
> > Once gpu_check_ok sees that the gpu is not hung I write 0
> > to stop_rings in order to clear it completely. This is
> > because igt_set_stop_rings will only write to stop_rings
> > if either a) they are currently 0 or b) we are writing 0.
> > If we leave the mode bits set then subsequent calls to
> > igt_set_stop_rings to create hangs will fail.
> 
> Can we please just deprecate the stop_rings interface? We can do
> explicit hang injection and GPU resets on gen4+, most of gen3 but not
> gen2. Even if we mask of testing for gen2/3, that still provides
> (almost, just a couple of gen2/3 reset functions will be missed) complete
> coverage of GEM reset handling.

Yeah I guess it's ok to nuke stop_rings. The only issue I see is that
stop_rings provided a neat way for the kernel to support gpu resets on
platforms where it's not working. I guess we'd need to move that knowledge
to igt with an require_gpu_reset macro and skip the tests correctly.
Otherwise I don't see an issue here really.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch