[Intel-gfx] [PATCH v7] drm/i915: Apply missed interrupt after reset w/a to all ringbuffer gen

[Chris Wilson]

Quoting Ville Syrjälä (2018-12-18 14:15:09)
> On Tue, Dec 18, 2018 at 10:27:12AM +0000, Chris Wilson wrote:
> > Having completed a test run of gem_eio across all machines in CI we also
> > observe the phenomenon (of lost interrupts after resetting the GPU) on
> > gen3 machines as well as the previously sighted gen6/gen7. Let's apply
> > the same HWSTAM workaround that was effective for gen6+ for all, as
> > although we haven't seen the same failure on gen4/5 it seems prudent to
> > keep the code the same.
> > 
> > As a consequence we can remove the extra setting of HWSTAM and apply the
> > register from a single site.
> > 
> > v2: Delazy and move the HWSTAM into its own function
> > v3: Mask off all HWSP writes on driver unload and engine cleanup.
> > v4: And what about the physical hwsp?
> > v5: No, engine->init_hw() is not called from driver_init_hw(), don't be
> > daft. Really scrub HWSTAM as early as we can in driver_init_mmio()
> > v6: Rename set_hwsp as it was setting the mask not the hwsp register.
> > v7: Ville pointed out that although vcs(bsd) was introduced for g4x/ilk,
> > per-engine HWSTAM was not introduced until gen6!
> > 
> > References: https://bugs.freedesktop.org/show_bug.cgi?id=108735
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Thanks a lot for the thorough checking. Hopefully this will be the last
we see of that blasted live_hangcheck failure on brw!
-Chris