ephyr: Fix crash on 24bpp host framebuffer

Use bytes_per_line and bits_per_pixel from the created XImage to fix
    https://bugzilla.redhat.com/show_bug.cgi?id=518960Signed-off-by: Daniel Martin <consume.noise@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

hw/kdrive/ephyr/ephyr.c

@@ -238,13 +238,11 @@ ephyrMapFramebuffer(KdScreenInfo * screen)
     KdComputePointerMatrix(&m, ephyrRandr, screen->width, screen->height);
     KdSetPointerMatrix(&m);
 
-    priv->bytes_per_line =
-        ((screen->width * screen->fb.bitsPerPixel + 31) >> 5) << 2;
-
     buffer_height = ephyrBufferHeight(screen);
 
     priv->base =
-        hostx_screen_init(screen, screen->width, screen->height, buffer_height);
+        hostx_screen_init(screen, screen->width, screen->height, buffer_height,
+                          &priv->bytes_per_line, &screen->fb.bitsPerPixel);
 
     if ((scrpriv->randr & RR_Rotate_0) && !(scrpriv->randr & RR_Reflect_All)) {
         scrpriv->shadow = FALSE;

hw/kdrive/ephyr/hostx.c

@@ -619,7 +619,8 @@ hostx_set_cmap_entry(unsigned char idx,
  */
 void *
 hostx_screen_init(EphyrScreenInfo screen,
-                  int width, int height, int buffer_height)
+                  int width, int height, int buffer_height,
+                  int *bytes_per_line, int *bits_per_pixel)
 {
     int bitmap_pad;
     Bool shm_success = False;
@@ -696,6 +697,9 @@ hostx_screen_init(EphyrScreenInfo screen,
             malloc(host_screen->ximg->bytes_per_line * buffer_height);
     }
 
+    *bytes_per_line = host_screen->ximg->bytes_per_line;
+    *bits_per_pixel = host_screen->ximg->bits_per_pixel;
+
     XResizeWindow(HostX.dpy, host_screen->win, width, height);
 
     /* Ask the WM to keep our size static */

hw/kdrive/ephyr/hostx.h

@@ -193,7 +193,8 @@ hostx_set_cmap_entry(unsigned char idx,
                      unsigned char r, unsigned char g, unsigned char b);
 
 void *hostx_screen_init(EphyrScreenInfo screen,
-                        int width, int height, int buffer_height);
+                        int width, int height, int buffer_height,
+                        int *bytes_per_line, int *bits_per_pixel);
 
 void