File u_06-Add-a-shadow_pixmap-to-hold-information-on-shadow_fb2.patch of Package xf86-video-modesetting.1041

From: Egbert Eich <eich@suse.de>
Date: Wed Aug 26 16:00:17 2015 +0200
Subject: [PATCH 6/6]Add a shadow_pixmap to hold information on shadow_fb2
Patch-mainline: to be upstreamed

References: bsc#942871
Signed-off-by: Egbert Eich <eich@suse.com>

The DIX shadow functions use a pixmap to retrieve data for the source
buffer. Since we use two shadow buffers we cannot use the screen pixmap.
Instead, create a copy of the screen pixmap for the intermediary shadow
buffer and modify the pointer to this buffer.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 src/driver.c          | 20 +++++++++++++++-----
 src/drmmode_display.c |  3 +++
 src/drmmode_display.h |  1 +
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/src/driver.c b/src/driver.c
index 70ee335..569d3b6 100644
--- a/src/driver.c
+++ b/src/driver.c
@@ -879,9 +879,9 @@ msUpdateIntersect(modesettingPtr ms, shadowBufPtr pBuf, BoxPtr box,
     for (i = box->y2 - box->y1 - 1; i >= 0; i--) {
 	unsigned char *o = old + i * stride,
 		      *n = new + i * stride;
-	if (memcmp(o, n, width) != 0) {
+	if (memcmp(n, o, width) != 0) {
 	    dirty = 1;
-	    memcpy(o, n, width);
+	    memcpy(n, o, width);
 	}
     }
 
@@ -977,18 +977,26 @@ CreateScreenResources(ScreenPtr pScreen)
 	pixels = ms->drmmode.shadow_fb;
 
     if (ms->drmmode.shadow_enable2) {
-	ms->drmmode.shadow_fb2 = calloc(1, pScrn->displayWidth * pScrn->virtualY * ((pScrn->bitsPerPixel + 7) >> 3));
+	ms->drmmode.shadow_pixmap = (PixmapPtr)calloc(1, sizeof(PixmapRec));
+	if (ms->drmmode.shadow_pixmap)
+	    ms->drmmode.shadow_fb2 = calloc(1, pScrn->displayWidth * pScrn->virtualY * ((pScrn->bitsPerPixel + 7) >> 3));
 	if (!ms->drmmode.shadow_fb2)
 	    ms->drmmode.shadow_enable2 = FALSE;
-	else
+	else {
 	    pixels = ms->drmmode.shadow_fb2;
+	    memcpy(ms->drmmode.shadow_pixmap, rootPixmap, sizeof(PixmapRec));
+	    if (!pScreen->ModifyPixmapHeader(ms->drmmode.shadow_pixmap,
+					     -1, -1, -1, -1, -1, ms->drmmode.shadow_fb))
+		FatalError("Couldn't adjust shadow pixmap\n");
+	}
     }
 
     if (!pScreen->ModifyPixmapHeader(rootPixmap, -1, -1, -1, -1, -1, pixels))
 	FatalError("Couldn't adjust screen pixmap\n");
 
     if (ms->drmmode.shadow_enable) {
-        if (!shadowAdd(pScreen, rootPixmap, msUpdatePacked, msShadowWindow,
+        if (!shadowAdd(pScreen, ms->drmmode.shadow_pixmap ? ms->drmmode.shadow_pixmap : rootPixmap,
+		       msUpdatePacked, msShadowWindow,
 		       0, 0))
 	    return FALSE;
     }
@@ -1252,6 +1260,8 @@ CloseScreen(CLOSE_SCREEN_ARGS_DECL)
 	ms->drmmode.shadow_fb = NULL;
         free(ms->drmmode.shadow_fb2);
         ms->drmmode.shadow_fb2 = NULL;
+	free(ms->drmmode.shadow_pixmap);
+	ms->drmmode.shadow_pixmap = NULL;
     }
     drmmode_uevent_fini(pScrn, &ms->drmmode);
 
diff --git a/src/drmmode_display.c b/src/drmmode_display.c
index 4de7cdc..cfb74a7 100644
--- a/src/drmmode_display.c
+++ b/src/drmmode_display.c
@@ -1219,6 +1219,9 @@ drmmode_xf86crtc_resize (ScrnInfoPtr scrn, int width, int height)
                 drmmode->shadow_fb2 = NULL;
             } else {
                 drmmode->shadow_fb2 = new_pixels;
+		memcpy(drmmode->shadow_pixmap, ppix, sizeof(PixmapRec));
+		screen->ModifyPixmapHeader(drmmode->shadow_pixmap,
+					   width, height, -1, -1, pitch, drmmode->shadow_fb);
             }
         }
 
diff --git a/src/drmmode_display.h b/src/drmmode_display.h
index 9096a2d..5f726cd 100644
--- a/src/drmmode_display.h
+++ b/src/drmmode_display.h
@@ -68,6 +68,7 @@ typedef struct {
     Bool shadow_enable2;
     void *shadow_fb;
     void *shadow_fb2;
+    PixmapPtr shadow_pixmap;
 
 #ifdef HAVE_SCREEN_SPECIFIC_PRIVATE_KEYS
     DevPrivateKeyRec pixmapPrivateKeyRec;