drm/radeon/kms: disable the r600 cb offset checker for linear surfaces

There are too many strange corner cases triggered in old userspace
drivers out there to that it's nearly impossible to not break some
obscure app.

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/r600_cs.c

@@ -315,11 +315,10 @@ static inline int r600_cs_track_validate_cb(struct radeon_cs_parser *p, int i)
 		if (array_mode == V_0280A0_ARRAY_LINEAR_GENERAL) {
 			/* the initial DDX does bad things with the CB size occasionally */
 			/* it rounds up height too far for slice tile max but the BO is smaller */
-			tmp = (height - 7) * 8 * bpe;
-			if ((tmp + track->cb_color_bo_offset[i]) > radeon_bo_size(track->cb_color_bo[i])) {
-				dev_warn(p->dev, "%s offset[%d] %d %d %lu too big\n", __func__, i, track->cb_color_bo_offset[i], tmp, radeon_bo_size(track->cb_color_bo[i]));
-				return -EINVAL;
-			}
+			/* r600c,g also seem to flush at bad times in some apps resulting in
+			 * bogus values here. So for linear just allow anything to avoid breaking
+			 * broken userspace.
+			 */
 		} else {
 			dev_warn(p->dev, "%s offset[%d] %d %d %lu too big\n", __func__, i, track->cb_color_bo_offset[i], tmp, radeon_bo_size(track->cb_color_bo[i]));
 			return -EINVAL;