[Mesa-dev] [PATCH] i965: Fix misapplication of gles3 srgb workaround

[Chad Versace]

Fixes inconsistent failure of gles2conform/GL2Tests/glUniform/glUniform.test
under gnome-shell. What follows is a description of the bug and its fix.

When intel_update_renderbuffers() allocates a miptree for a winsys
renderbuffer, it propagates the renderbuffer's format to become also the
miptree's format.

If the winsys color buffer format is SARGB, then, in the first call to
eglMakeCurrent, intel_gles3_srgb_workaround() changes the renderbuffer's
format to ARGB. That is, it changes the format from sRGB to non-sRGB.
However, it changes the renderbuffer's format *after*
intel_update_renderbuffers() has allocated the renderbuffer's miptree.
Therefore, when eglMakeCurrent returns, the miptree format (SARGB)
differs from the renderbuffer format (ARGB).

If the X server reallocates the color buffer,
intel_update_renderbuffers() will create a new miptree for the
renderbuffer. The new miptree's format (ARGB) will differ from old
miptree's format (SARGB). This mismatch between old and new miptrees
causes bugs.

Fix the bug by moving intel_gles3_srgb_workaround() to occur *before*
intel_update_renderbuffers().

CC: "9.2" <mesa-stable at lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67934
Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---
 src/mesa/drivers/dri/i965/intel_context.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_context.c b/src/mesa/drivers/dri/i965/intel_context.c
index 2e38475..37c1770 100644
--- a/src/mesa/drivers/dri/i965/intel_context.c
+++ b/src/mesa/drivers/dri/i965/intel_context.c
@@ -755,11 +755,15 @@ intelMakeCurrent(__DRIcontext * driContextPriv,
 	 driContextPriv->dri2.read_stamp = driReadPriv->dri2.stamp - 1;
       }
 
+      /* The sRGB workaround changes the renderbuffer's format. We must change
+       * the format before the renderbuffer's miptree get's allocated, otherwise
+       * the formats of the renderbuffer and its miptree will differ.
+       */
+      intel_gles3_srgb_workaround(brw, fb);
+      intel_gles3_srgb_workaround(brw, readFb);
+
       intel_prepare_render(brw);
       _mesa_make_current(ctx, fb, readFb);
-
-      intel_gles3_srgb_workaround(brw, ctx->WinSysDrawBuffer);
-      intel_gles3_srgb_workaround(brw, ctx->WinSysReadBuffer);
    }
    else {
       _mesa_make_current(NULL, NULL, NULL);
-- 
1.8.3.1