[PATCH xf86-video-ati] Use correct ScrnInfoPtr in redisplay_dirty

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

We used the destination pixmap's screen for flushing drawing commands.
But when we are the master screen, the destination pixmap is from the
slave screen.

Fixes crash when the slave screen isn't using the same acceleration
architecture as us.

Bugzilla: https://bugs.freedesktop.org/103613
Fixes: 01b040b4a807 ("Adapt to PixmapDirtyUpdateRec::src being a
                     DrawablePtr")
(Ported from amdgpu commit 3a4f7422913093ed9e26b73ecd7f9e773478cb1e)

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 src/radeon_kms.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/radeon_kms.c b/src/radeon_kms.c
index 06c8a47fb..5fcd8f0b7 100644
--- a/src/radeon_kms.c
+++ b/src/radeon_kms.c
@@ -570,7 +570,11 @@ dirty_region(PixmapDirtyUpdatePtr dirty)
 static void
 redisplay_dirty(PixmapDirtyUpdatePtr dirty, RegionPtr region)
 {
-	ScrnInfoPtr pScrn = xf86ScreenToScrn(dirty->slave_dst->drawable.pScreen);
+#ifdef HAS_DIRTYTRACKING_DRAWABLE_SRC
+	ScrnInfoPtr src_scrn = xf86ScreenToScrn(dirty->src->pScreen);
+#else
+	ScrnInfoPtr src_scrn = xf86ScreenToScrn(dirty->src->drawable.pScreen);
+#endif
 
 	if (RegionNil(region))
 		goto out;
@@ -584,7 +588,7 @@ redisplay_dirty(PixmapDirtyUpdatePtr dirty, RegionPtr region)
 	PixmapSyncDirtyHelper(dirty, region);
 #endif
 
-	radeon_cs_flush_indirect(pScrn);
+	radeon_cs_flush_indirect(src_scrn);
 	if (dirty->slave_dst->master_pixmap)
 	    DamageRegionProcessPending(&dirty->slave_dst->drawable);
 
-- 
2.15.0