Mesa (10.4): radeonsi: Disable asynchronous DMA except for PIPE_BUFFER

[Emil Velikov]

Module: Mesa
Branch: 10.4
Commit: 5a2ff2002be7143b8a44d74c3f204c6a659a88bc
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=5a2ff2002be7143b8a44d74c3f204c6a659a88bc

Author: Michel Dänzer <michel.daenzer at amd.com>
Date:   Tue Nov 11 16:10:20 2014 +0900

radeonsi: Disable asynchronous DMA except for PIPE_BUFFER

Using the asynchronous DMA engine for multi-dimensional operations seems
to cause random GPU lockups for various people. While the root cause for
this might need to be fixed in the kernel, let's disable it for now.

Before re-enabling this, please make sure you can hit all newly enabled
paths in your testing, preferably with both piglit and real world apps,
and get in touch with people on the bug reports below for stability
testing.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85647
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83500
Cc: "10.3 10.4" <mesa-stable at lists.freedesktop.org>
Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Reviewed-by: Grigori Goronzy <greg at chown.ath.cx>
(cherry picked from commit ae4536b4f71cbe76230ea7edc7eb4d6041e651b4)

---

 src/gallium/drivers/radeonsi/si_dma.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/gallium/drivers/radeonsi/si_dma.c b/src/gallium/drivers/radeonsi/si_dma.c
index b1bd5e7..db523ee 100644
--- a/src/gallium/drivers/radeonsi/si_dma.c
+++ b/src/gallium/drivers/radeonsi/si_dma.c
@@ -250,6 +250,21 @@ void si_dma_copy(struct pipe_context *ctx,
 		return;
 	}
 
+	/* XXX: Using the asynchronous DMA engine for multi-dimensional
+	 * operations seems to cause random GPU lockups for various people.
+	 * While the root cause for this might need to be fixed in the kernel,
+	 * let's disable it for now.
+	 *
+	 * Before re-enabling this, please make sure you can hit all newly
+	 * enabled paths in your testing, preferably with both piglit and real
+	 * world apps, and get in touch with people on the bug reports below
+	 * for stability testing.
+	 *
+	 * https://bugs.freedesktop.org/show_bug.cgi?id=85647
+	 * https://bugs.freedesktop.org/show_bug.cgi?id=83500
+	 */
+	goto fallback;
+
 	if (src->format != dst->format || src_box->depth > 1 ||
 	    rdst->dirty_level_mask != 0 ||
 	    rdst->cmask.size || rdst->fmask.size ||