<div dir="ltr">Adding people who may have some shot at understanding this stuff </div><div class="gmail_extra"> <div class="gmail_quote">On Tue, Sep 12, 2017 at 4:23 PM, Jason Ekstrand <<a href="mailto:jason@jlekstrand.net" target="_blank">jason@jlekstrand.net</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">The setTexBuffer2 hook from GLX is used to implement glxBindTexImageEXT which has tighter restrictions than just "it's shared". In particular, it says that any rendering to the image while it is bound causes the contents to become undefined. This means that we can do whatever aux tracking we want between glxBindTexImageEXT and glxReleaseTexImageEXT so long as we always transition from external in Bind and to external in Release. The fact that we were using make_shareable before was a problem because it would resolve away 100% of the aux data and then throw away our reference to the aux buffer. If the aux data was shared with some other application (i.e. if we're using I915_FORMAT_MOD_Y_TILED_CCS) then we would forget that the aux data even existed for the rest of eternity. This is fine for the first frame but any subsequent calls to glxBindTexImageEXT would bind the texture as if it has no aux whatsoever and no resolves would happen and texturing would happen as if there is no aux. This was causing rendering corruption in mutter when running on top of X11 with modifiers. --- src/mesa/drivers/dri/i965/intel_tex_image.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/intel_tex_image.c b/src/mesa/drivers/dri/i965/intel_tex_image.c index 09ff287..0e8a947 100644 --- a/src/mesa/drivers/dri/i965/intel_tex_image.c +++ b/src/mesa/drivers/dri/i965/intel_tex_image.c @@ -251,7 +251,7 @@ intelSetTexBuffer2(__DRIcontext *pDRICtx, GLint target, internal_format = GL_RGB; } - intel_miptree_make_shareable(brw, rb->mt); + intel_miptree_prepare_external(brw, rb->mt); _mesa_lock_texture(&brw->ctx, texObj); texImage = _mesa_get_tex_image(ctx, texObj, target, 0); -- 2.5.0.400.gff86faf </blockquote></div> </div>