[Mesa-dev] [PATCH] i965: Don't try to resolve CCS with MESA_FORMAT_NONE.

[Kenneth Graunke]

Since commit e9f5004d5ea38a21019e0affcd63d353b98d499a, KDE's Plasma
Shell started crashing when intel_disable_rb_aux_buffer tried to
dereference irb->mt, and there was no miptree.  This happened during
intel_texture_view_requires_resolve, coming from a glClear().

Apparently intel_tex->_Format is MESA_FORMAT_NONE.  We used to translate
MESA_FORMAT_NONE to 0, which happens to be ISL_FORMAT_R32G32B32A32_FLOAT,
which happens to support CCS_E, so we assumed no resolves were needed.

That patch began translating MESA_FORMAT_NONE as ISL_FORMAT_UNSUPPORTED,
which claims not to support CCS_E, so we thought we needed resolves,
even though the buffer was in a bad state.

For now, detect intel_tex->_Format == MESA_FORMAT_NONE and bail, like
we used to.  This is an ugly band-aid fix, but that's okay, given that
Jason has patches on the mailing list to rewrite the resolve code.

This makes KDE usable again.
---
 src/mesa/drivers/dri/i965/brw_context.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 9878cae9d4b..d8219cb57e0 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -205,6 +205,9 @@ intel_texture_view_requires_resolve(struct brw_context *brw,
        !intel_miptree_is_lossless_compressed(brw, intel_tex->mt))
      return false;
 
+   if (intel_tex->_Format == MESA_FORMAT_NONE)
+      return false;
+
    const enum isl_format isl_format =
       brw_isl_format_for_mesa_format(intel_tex->_Format);
 
-- 
2.13.0