[Mesa-stable] [Mesa-dev] [PATCH] drirc: Disable ARB_blend_func_extended for Heaven 4.0/Valley 1.0.

[Marek Olšák]

On Mon, Dec 28, 2015 at 11:28 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> Unigine Heaven 4.0 and Valley 1.0 use dual color blending but don't
> specify which fragment shader output is which, so there's at best a
> 50/50 chance of us guessing it correctly.  This is invalid.
>
> Unigine fixed this in 4.1 and 1.1 versions over a year and a half ago,
> but hasn't actually released them for whatever reason.  So, add the
> workaround back so that it works for most people.
>
> Fixes Heaven 4.0/Valley 1.0 rendering on Ivybridge.  For whatever
> reason, Broadwell worked.  4.1 and 1.1 have always worked.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92233
> Cc: mesa-stable at lists.freedesktop.org
> Cc: Marek Olšák <marek.olsak at amd.com>

Hi Ken,

We've never had a problem with this in gallium, but if it's just luck,
I suppose it's okay to add the workaround.

In Gallium, the second color output is the same as gl_FragData[1], so
it doesn't matter how the location is specified as long as it's clear
which output goes second.

How difficult is it to be unlucky here? Does it depend on IR node ordering?

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

Marek