V4L/DVB (4377): Force horizontal resolution limits in the pvrusb2 driver

This change causes the pvrusb2 driver to limit horizontal resolution
to be only 720 if 24xxx device hardware is being used.  This is a
workaround for an unsolved problem in the driver where if the
resolution is set to something other than 720 the video quality will
be _seriously_ degraded.  It only happens on 24xxx devices (29xxx are
unaffected by the problem and unaffected by this change).  Once the
problem is finally solved, this small change can be removed.
Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/pvrusb2/pvrusb2-hdw.c

@@ -363,6 +363,30 @@ static int ctrl_freq_set(struct pvr2_ctrl *cptr,int m,int v)
 	return 0;
 }
 
+#ifdef CONFIG_VIDEO_PVRUSB2_24XXX
+static int ctrl_hres_max_get(struct pvr2_ctrl *cptr,int *vp)
+{
+	/* If we're dealing with a 24xxx device, force the horizontal
+	   maximum to be 720 no matter what, since we can't get the device
+	   to work properly with any other value.  Otherwise just return
+	   the normal value. */
+	*vp = cptr->info->def.type_int.max_value;
+	if (cptr->hdw->hdw_type == PVR2_HDW_TYPE_24XXX) *vp = 720;
+	return 0;
+}
+
+static int ctrl_hres_min_get(struct pvr2_ctrl *cptr,int *vp)
+{
+	/* If we're dealing with a 24xxx device, force the horizontal
+	   minimum to be 720 no matter what, since we can't get the device
+	   to work properly with any other value.  Otherwise just return
+	   the normal value. */
+	*vp = cptr->info->def.type_int.min_value;
+	if (cptr->hdw->hdw_type == PVR2_HDW_TYPE_24XXX) *vp = 720;
+	return 0;
+}
+#endif
+
 static int ctrl_cx2341x_is_dirty(struct pvr2_ctrl *cptr)
 {
 	return cptr->hdw->enc_stale != 0;
@@ -721,6 +745,12 @@ static const struct pvr2_ctl_info control_defs[] = {
 		.default_value = 720,
 		DEFREF(res_hor),
 		DEFINT(320,720),
+#ifdef CONFIG_VIDEO_PVRUSB2_24XXX
+		/* Hook in check for clamp on horizontal resolution in
+		   order to avoid unsolved problem involving cx25840. */
+		.get_max_value = ctrl_hres_max_get,
+		.get_min_value = ctrl_hres_min_get,
+#endif
 	},{
 		.desc = "Vertical capture resolution",
 		.name = "resolution_ver",