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ALSA: usb-audio: reduce MIDI packet size to work around broken firmware 

Extend the list of devices whose firmware does not expect more than one
USB MIDI packet in one USB packet.

bug report: https://bugtrack.alsa-project.org/alsa-bug/view.php?id=3752

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Clemens Ladisch 2010-02-15 08:55:28 +01:00 committed by Jaroslav Kysela
parent 9d4c746445
commit f167e1d073
1 changed files with 15 additions and 3 deletions
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18
sound/usb/usbmidi.c
View File

@ -1162,10 +1162,22 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi* umidi,
pipe = usb_sndintpipe(umidi->dev, ep_info->out_ep);
else
pipe = usb_sndbulkpipe(umidi->dev, ep_info->out_ep);
if (umidi->usb_id == USB_ID(0x0a92, 0x1020)) /* ESI M4U */
ep->max_transfer = 4;
else
switch (umidi->usb_id) {
default:
ep->max_transfer = usb_maxpacket(umidi->dev, pipe, 1);
break;
/*
* Various chips declare a packet size larger than 4 bytes, but
* do not actually work with larger packets:
*/
case USB_ID(0x0a92, 0x1020): /* ESI M4U */
case USB_ID(0x1430, 0x474b): /* RedOctane GH MIDI INTERFACE */
case USB_ID(0x15ca, 0x0101): /* Textech USB Midi Cable */
case USB_ID(0x15ca, 0x1806): /* Textech USB Midi Cable */
case USB_ID(0x1a86, 0x752d): /* QinHeng CH345 "USB2.0-MIDI" */
ep->max_transfer = 4;
break;
}
for (i = 0; i < OUTPUT_URBS; ++i) {
buffer = usb_buffer_alloc(umidi->dev,
ep->max_transfer, GFP_KERNEL,