From: Devin Heitmueller Date: Thu, 28 May 2009 02:23:37 +0000 (-0300) Subject: V4L/DVB (11923): em28xx: Don't let device work unless connected to a high speed USB... X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=64a00b43e63c916f1bf4f6b7f519db0e198ba9d4;p=deliverable%2Flinux.git V4L/DVB (11923): em28xx: Don't let device work unless connected to a high speed USB port The em28xx 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. Signed-off-by: Devin Heitmueller Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c index fe2a471e5f64..72cab9bcdf95 100644 --- a/drivers/media/video/em28xx/em28xx-cards.c +++ b/drivers/media/video/em28xx/em28xx-cards.c @@ -2365,6 +2365,20 @@ static int em28xx_usb_probe(struct usb_interface *interface, ifnum, interface->altsetting->desc.bInterfaceNumber); + /* + * 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 (udev->speed != USB_SPEED_HIGH) { + printk(DRIVER_NAME ": Device initialization failed.\n"); + printk(DRIVER_NAME ": Device must be connected to a high-speed" + " USB 2.0 port.\n"); + em28xx_devused &= ~(1<= EM28XX_MAXBOARDS) { printk(DRIVER_NAME ": Supports only %i em28xx boards.\n", EM28XX_MAXBOARDS);