[Mesa-dev] [PATCH] i965/cnl: Avoid fast-clearing sRGB render buffers

[Nanley Chery]

On Fri, Dec 01, 2017 at 04:42:22PM -0800, Jason Ekstrand wrote:
> On Fri, Dec 1, 2017 at 2:44 PM, Nanley Chery <nanleychery at gmail.com> wrote:
> 
> > Gen10 doesn't automatically decode the clear color of sRGB buffers. To
> > get correct rendering, avoid fast-clearing such buffers for now.
> >
> > The driver now passes the following piglit tests:
> > * spec at arb_framebuffer_srgb@msaa-fast-clear
> > * spec at ext_texture_srgb@multisample-fast-clear gl_ext_texture_srgb
> >
> > Suggested-by: Kenneth Graunke <kenneth at whitecape.org>
> > Suggested-by: Jason Ekstrand <jason at jlekstrand.net>
> > Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
> > ---
> >
> > This patch is currently going through the jenkins pipeline.
> >
> >  src/mesa/drivers/dri/i965/brw_meta_util.c | 14 ++++++++++++--
> >  1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/brw_meta_util.c
> > b/src/mesa/drivers/dri/i965/brw_meta_util.c
> > index ba92168934..54dc6a5ff9 100644
> > --- a/src/mesa/drivers/dri/i965/brw_meta_util.c
> > +++ b/src/mesa/drivers/dri/i965/brw_meta_util.c
> > @@ -298,13 +298,23 @@ brw_is_color_fast_clear_compatible(struct
> > brw_context *brw,
> >      * resolved in intel_update_state. In that case it's pointless to do a
> >      * fast clear because it's very likely to be immediately resolved.
> >      */
> > +   const bool srgb_rb = _mesa_get_srgb_format_linear(mt->format) !=
> > mt->format;
> >     if (devinfo->gen >= 9 &&
> >         mt->surf.samples == 1 &&
> > -       ctx->Color.sRGBEnabled &&
> > -       _mesa_get_srgb_format_linear(mt->format) != mt->format)
> > +       ctx->Color.sRGBEnabled && srgb_rb)
> >        return false;
> >
> > +  /* Gen10 doesn't automatically decode the clear color of sRGB buffers.
> > Since
> > +   * we currently don't perform this decode in software, avoid a
> > fast-clear
> > +   * altogether. TODO: Do this in software.
> > +   */
> >     const mesa_format format = _mesa_get_render_format(ctx, mt->format);
> > +   if (devinfo->gen >= 10 && srgb_rb) {
> >
> 
> We could be a bit more precise and only disable it for non-0/1.  Either way,
> 
> Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
> 
> 


Thanks! I'm gonna push this and hopefully we'll get around to using the
packed clear method to solve all the corner cases.

> > +      perf_debug("sRGB fast clear not enabled for (%s)",
> > +                 _mesa_get_format_name(format));
> >
> 
> Thanks for leaving a perf_debug!
> 
> 

Np, I was inspired by the one nearby :)

-Nanley

> > +      return false;
> > +   }
> > +
> >     if (_mesa_is_format_integer_color(format)) {
> >        if (devinfo->gen >= 8) {
> >           perf_debug("Integer fast clear not enabled for (%s)",
> > --
> > 2.15.1
> >
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> >