[media] em28xx: increase maxwidth for em2800

The MaxPacketSize for em2800 based devices is too small to capture at full resolution.
Therefore scale down when the maximum frame size is selected.
The previous workaround that simply reduced the X resolution cannot be used
because it crops a part of the input as
the em2800 can only scale down with a factor of 0.5.

reverts commits 1ca31892 and fb3de039.

[mchehab@redhat.com: Fix CodingStyle]
Signed-off-by: Sascha Sommer <saschasommer@freenet.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx-video.c

@@ -1070,6 +1070,10 @@ static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
 		/* the em2800 can only scale down to 50% */
 		height = height > (3 * maxh / 4) ? maxh : maxh / 2;
 		width = width > (3 * maxw / 4) ? maxw : maxw / 2;
+                /* MaxPacketSize for em2800 is too small to capture at full resolution
+                 * use half of maxw as the scaler can only scale to 50% */
+		if (width == maxw && height == maxh)
+			width /= 2;
 	} else {
 		/* width must even because of the YUYV format
 		   height must be even because of interlacing */
@@ -2503,6 +2507,7 @@ int em28xx_register_analog_devices(struct em28xx *dev)
 {
       u8 val;
 	int ret;
+	unsigned int maxw;
 
 	printk(KERN_INFO "%s: v4l2 driver version %s\n",
 		dev->name, EM28XX_VERSION);
@@ -2515,8 +2520,15 @@ int em28xx_register_analog_devices(struct em28xx *dev)
 
 	/* Analog specific initialization */
 	dev->format = &format[0];
+
+	maxw = norm_maxw(dev);
+        /* MaxPacketSize for em2800 is too small to capture at full resolution
+         * use half of maxw as the scaler can only scale to 50% */
+        if (dev->board.is_em2800)
+            maxw /= 2;
+
 	em28xx_set_video_format(dev, format[0].fourcc,
-				norm_maxw(dev), norm_maxh(dev));
+				maxw, norm_maxh(dev));
 
 	video_mux(dev, dev->ctl_input);
 

drivers/media/video/em28xx/em28xx.h

@@ -831,7 +831,7 @@ static inline unsigned int norm_maxw(struct em28xx *dev)
 	if (dev->board.is_webcam)
 		return dev->sensor_xres;
 
-	if (dev->board.max_range_640_480 || dev->board.is_em2800)
+	if (dev->board.max_range_640_480)
 		return 640;
 
 	return 720;