[07/12] BACKPORT: vnc: fix copyrect screen corruption

Submitted by Glauber Costa on Aug. 26, 2009, 1:05 p.m.

Details

Message ID 1251291946-25821-8-git-send-email-glommer@redhat.com
State Superseded
Headers show

Commit Message

Glauber Costa Aug. 26, 2009, 1:05 p.m.
From: Gerd Hoffmann <kraxel@redhat.com>

When sending a copyrect command to the vnc client, we must also update
the local server surface.  Otherwise the server's and the client's idea
of the screen content run out of sync and screen updates don't work
correctly.

[ backport: uses ds_get_data() instead of direct dereference ]
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 vnc.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)

Comments

Mark McLoughlin Oct. 1, 2009, 9:21 a.m.
Hey,

On Wed, 2009-08-26 at 09:05 -0400, Glauber Costa wrote:
> From: Gerd Hoffmann <kraxel@redhat.com>
> 
> When sending a copyrect command to the vnc client, we must also update
> the local server surface.  Otherwise the server's and the client's idea
> of the screen content run out of sync and screen updates don't work
> correctly.
> 
> [ backport: uses ds_get_data() instead of direct dereference ]

We have reports from two Fedora 11 users that this fix makes things
worse:

  https://bugzilla.redhat.com/503156

Cheers,
Mark.

Patch hide | download patch | download mbox

diff --git a/vnc.c b/vnc.c
index 1d8ebe7..c0700c0 100644
--- a/vnc.c
+++ b/vnc.c
@@ -633,8 +633,14 @@  static void send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
 
 static void vnc_copy(VncState *vs, int src_x, int src_y, int dst_x, int dst_y, int w, int h)
 {
+
+    uint8_t *src_row;
+    uint8_t *dst_row;
+    int y,pitch,depth;
+
     vnc_update_client(vs);
 
+    /* send bitblit op to the vnc client */
     vnc_write_u8(vs, 0);  /* msg id */
     vnc_write_u8(vs, 0);
     vnc_write_u16(vs, 1); /* number of rects */
@@ -642,6 +648,23 @@  static void vnc_copy(VncState *vs, int src_x, int src_y, int dst_x, int dst_y, i
     vnc_write_u16(vs, src_x);
     vnc_write_u16(vs, src_y);
     vnc_flush(vs);
+
+    /* do bitblit op on the local surface too */
+    pitch = ds_get_linesize(vs->ds);
+    depth = ds_get_bytes_per_pixel(vs->ds);
+    src_row = ds_get_data(vs->ds) + pitch * src_y + depth * src_x;
+    dst_row = ds_get_data(vs->ds) + pitch * dst_y + depth * dst_x;
+    if (dst_y > src_y) {
+        /* copy backwards */
+        src_row += pitch * (h-1);
+        dst_row += pitch * (h-1);
+        pitch = -pitch;
+    }
+    for (y = 0; y < h; y++) {
+        memmove(dst_row, src_row, w * depth);
+        src_row += pitch;
+        dst_row += pitch;
+    }
 }
 
 static void vnc_dpy_copy(DisplayState *ds, int src_x, int src_y, int dst_x, int dst_y, int w, int h)