V4L/DVB: saa7146: fix up bytesperline if it is an impossible value

xawtv using DGA on a Radeon graphics card provides bogus
values to S_FBUF, which will then screw up overlay video:

https://bugs.launchpad.net/ubuntu/+source/xawtv/+bug/499734

This fixes the bytesperline value if it is off completely.

Signed-off-by: Michael Hunold <michael@mihu.de>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/common/saa7146_video.c b/drivers/media/common/saa7146_video.c
index 5ed7526..b8b2c55 100644 (file)
--- a/drivers/media/common/saa7146_video.c
+++ b/drivers/media/common/saa7146_video.c
@@ -558,9 +558,11 @@ static int vidioc_s_fbuf(struct file *file, void *fh, struct v4l2_framebuffer *f
        /* ok, accept it */
        vv->ov_fb = *fb;
        vv->ov_fmt = fmt;
-       if (0 == vv->ov_fb.fmt.bytesperline)
-               vv->ov_fb.fmt.bytesperline =
-                       vv->ov_fb.fmt.width * fmt->depth / 8;
+
+       if (vv->ov_fb.fmt.bytesperline < vv->ov_fb.fmt.width) {
+               vv->ov_fb.fmt.bytesperline = vv->ov_fb.fmt.width * fmt->depth / 8;
+               DEB_D(("setting bytesperline to %d\n", vv->ov_fb.fmt.bytesperline));
+       }
 
        mutex_unlock(&dev->lock);
        return 0;