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ephyr: Ensure stride of private framebuffer is multiple of 4

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The fb layer of X can't deal with strides that are not a multiple of
4, so when Xephyr allocates its own framebuffer it should make sure to
align it.

This fixes crashes and rendering corruption when Xephyr runs in a
depth that is different from the host X server and its screen size is
not a multiple of 4 / depth. (This is particularly easy to trigger if
you use the -resizeable option).

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Soren Sandmann <ssp@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
This commit is contained in:
Søren Sandmann Pedersen 2013-10-21 17:11:56 -04:00 committed by Keith Packard
parent 97cf53cc2a
commit 623c414765
1 changed files with 8 additions and 7 deletions
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15
hw/kdrive/ephyr/hostx.c
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@ -721,12 +721,14 @@ hostx_screen_init(KdScreenInfo *screen,
return scrpriv->ximg->data;
}
else {
*bytes_per_line = width * (scrpriv->server_depth >> 3);
int bytes_per_pixel = scrpriv->server_depth >> 3;
int stride = (width * bytes_per_pixel + 0x3) & ~0x3;
*bytes_per_line = stride;
*bits_per_pixel = scrpriv->server_depth;
EPHYR_DBG("server bpp %i", scrpriv->server_depth >> 3);
scrpriv->fb_data =
malloc(width * buffer_height * (scrpriv->server_depth >> 3));
EPHYR_DBG("server bpp %i", bytes_per_pixel);
scrpriv->fb_data = malloc (stride * buffer_height);
return scrpriv->fb_data;
}
}
@ -765,15 +767,14 @@ hostx_paint_rect(KdScreenInfo *screen,
if (!host_depth_matches_server(scrpriv)) {
int x, y, idx, bytes_per_pixel = (scrpriv->server_depth >> 3);
int stride = (scrpriv->win_width * bytes_per_pixel + 0x3) & ~0x3;
unsigned char r, g, b;
unsigned long host_pixel;
EPHYR_DBG("Unmatched host depth scrpriv=%p\n", scrpriv);
for (y = sy; y < sy + height; y++)
for (x = sx; x < sx + width; x++) {
idx =
(scrpriv->win_width * y * bytes_per_pixel) +
(x * bytes_per_pixel);
idx = y * stride + x * bytes_per_pixel;
switch (scrpriv->server_depth) {
case 16: