[Intel-gfx] [PATCH i-g-t] i915/gem_workarounds: Verify regs directly

[Chris Wilson]

Quoting Chris Wilson (2019-05-29 10:58:05)
> It seems like the HW validator is getting better at preventing our
> snooping of system registers from non-privileged batches! If we can't
> use SRM, let's probe the register directly through mmio, making sure we
> have the context spinning on the GPU first.
> 
> v2: Hold forcewake just in case the spinning batch isn't enough to
> justify our register access.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110544
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Matthew Auld <matthew.william.auld at gmail.com>

Carried over from v1,
Reviewed-by: Matthew Auld <matthew.william.auld at gmail.com>
-Chris