[Intel-gfx] [PATCH v2] drm/i915: Add the predicate source registers to the register whitelist

[Daniel Vetter]

On Fri, Jan 09, 2015 at 04:41:10PM +0000, Neil Roberts wrote:
> Hi,
>
> Daniel Vetter <daniel at ffwll.ch> writes:
>
> > Ok, I've merged this one, since that means you at least won't get an
> > -EINVAL. But you can't yet enable the feature in mesa since it's still
> > no-opped out. Let's hope that v3 actually starts granting rights (but
> > please don't encode that in any merge mesa patch before it's official in
> > the kernel, Dave Airlie _will_ revert it even if it breaks the build) and
> > that this happens soon.
>
> Thanks for merging the patch.
>
> The current patch proposed for Mesa only enables the feature if the
> version is >= 2 *and* it can successfully do a pipeline write to some
> other register. Checking whether it can write to a register is already
> used to decide whether to enable some transform feedback extensions and
> indirect draw calls. I think in that case it should be safe to land the
> Mesa patches even though it would only work on IvyBridge and not Haswell
> or Gen8+. If we fix the kernel to allow the write for Haswell too then I
> think it would magically start working without any extra changes. I'm
> not really sure if I understand what you're saying about it being
> no-opped. It's effectively not no-opped on IvyBridge so I think we
> should already be able to enable the feature. Do you agree?

Makes sense, thanks for clarifying.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch