From 447df5eabac62d11740b23987cf91fb269bffcc6 Mon Sep 17 00:00:00 2001 From: Paul Berry Date: Wed, 29 May 2013 09:48:26 -0700 Subject: [PATCH] intel: flush fake front buffer more robustly. When a fake front buffer is in use, if we request the front buffer (using screen->dri2.loader->getBuffersWithFormat()), the X server copies the real front buffer to the fake front buffer and returns the fake front buffer. We sometimes make redundant requests for the front buffer (due to using a single counter to track invalidates for both the front and back buffers), so there's a danger of pending front buffer rendering getting overwritten when the redundant front buffer request occurs. Previous to this patch, intel_update_renderbuffers() worked around that problem by sometimes doing intel_flush() and intel_flush_front() before calling intel_query_dri2_buffers(). But it only did the workaround when the front buffer was bound for drawing; it didn't do it when the front buffer was bound for reading. This patch moves the workaround code to intel_query_dri2_buffers(), so that it happens in exactly the circumstances where it is needed. This should fix some of the sporadic failures in Piglit tests fbo-sys-blit and fbo-sys-sub-blit. Reviewed-by: Chad Versace Reviewed-by: Anuj Phogat --- src/mesa/drivers/dri/intel/intel_context.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c index 54d0a69edc7..7f8a2bbfa8c 100644 --- a/src/mesa/drivers/dri/intel/intel_context.c +++ b/src/mesa/drivers/dri/intel/intel_context.c @@ -186,17 +186,6 @@ intel_update_renderbuffers(__DRIcontext *context, __DRIdrawable *drawable) int i, count; const char *region_name; - /* If we're rendering to the fake front buffer, make sure all the - * pending drawing has landed on the real front buffer. Otherwise - * when we eventually get to DRI2GetBuffersWithFormat the stale - * real front buffer contents will get copied to the new fake front - * buffer. - */ - if (intel->is_front_buffer_rendering) { - intel_flush(&intel->ctx); - intel_flush_front(&intel->ctx); - } - /* Set this up front, so that in case our buffers get invalidated * while we're getting new buffers, we don't clobber the stamp and * thus ignore the invalidate. */ @@ -925,6 +914,15 @@ intel_query_dri2_buffers(struct intel_context *intel, if ((intel->is_front_buffer_rendering || intel->is_front_buffer_reading || !back_rb) && front_rb) { + /* If a fake front buffer is in use, then querying for + * __DRI_BUFFER_FRONT_LEFT will cause the server to copy the image from + * the real front buffer to the fake front buffer. So before doing the + * query, we need to make sure all the pending drawing has landed in the + * real front buffer. + */ + intel_flush(&intel->ctx); + intel_flush_front(&intel->ctx); + attachments[i++] = __DRI_BUFFER_FRONT_LEFT; attachments[i++] = intel_bits_per_pixel(front_rb); } -- 2.30.2