[ALSA] usb-audio: work around wrong wMaxPacketSize on ESI M4U

Add a workaround for the ESI M4U that claims to support 32-byte packets
but ignores the remaining bytes of packets bigger than four bytes.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
This commit is contained in:
Clemens Ladisch 2007-05-07 09:29:32 +02:00 committed by Jaroslav Kysela
parent d05cc10432
commit 490cbd92ed

View File

@ -965,7 +965,11 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi* umidi,
}
/* we never use interrupt output pipes */
pipe = usb_sndbulkpipe(umidi->chip->dev, ep_info->out_ep);
ep->max_transfer = usb_maxpacket(umidi->chip->dev, pipe, 1);
if (umidi->chip->usb_id == USB_ID(0x0a92, 0x1020)) /* ESI M4U */
/* FIXME: we need more URBs to get reasonable bandwidth here: */
ep->max_transfer = 4;
else
ep->max_transfer = usb_maxpacket(umidi->chip->dev, pipe, 1);
buffer = usb_buffer_alloc(umidi->chip->dev, ep->max_transfer,
GFP_KERNEL, &ep->urb->transfer_dma);
if (!buffer) {