From 7e58cab3858aad1f493903e63dab1b90bdcc9f27 Mon Sep 17 00:00:00 2001 From: Devin Heitmueller Date: Wed, 27 May 2009 22:25:36 -0400 Subject: au0828: Don't let device work unless connected to a high speed USB port From: Devin Heitmueller The au0828 basically just doesn't work at 12 Mbps. The isoc pipe needs nearly 200 Mbps for analog support, so users would see garbage video, and on the DVB/ATSC side scanning is likely to work but if the user tried to tune it would certainly appear to have failed. It's better to fail explicity up front and tell the user to plug into a USB 2.0 port, than to let the driver load and the user have weird problems with tuning and garbage video. Priority: normal Signed-off-by: Devin Heitmueller --- linux/drivers/media/video/au0828/au0828-core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'linux/drivers/media/video/au0828') diff --git a/linux/drivers/media/video/au0828/au0828-core.c b/linux/drivers/media/video/au0828/au0828-core.c index 4da5b7909..d52d66bfd 100644 --- a/linux/drivers/media/video/au0828/au0828-core.c +++ b/linux/drivers/media/video/au0828/au0828-core.c @@ -182,6 +182,18 @@ static int au0828_usb_probe(struct usb_interface *interface, le16_to_cpu(usbdev->descriptor.idProduct), ifnum); + /* + * Make sure we have 480 Mbps of bandwidth, otherwise things like + * video stream wouldn't likely work, since 12 Mbps is generally + * not enough even for most Digital TV streams. + */ + if (usbdev->speed != USB_SPEED_HIGH) { + printk(KERN_ERR "au0828: Device initialization failed.\n"); + printk(KERN_ERR "au0828: Device must be connected to a " + "high-speed USB 2.0 port.\n"); + return -ENODEV; + } + dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (dev == NULL) { printk(KERN_ERR "%s() Unable to allocate memory\n", __func__); -- cgit v1.2.3