Commit f167e1d0 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Jaroslav Kysela

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=3752Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: default avatarJaroslav Kysela <perex@perex.cz>
parent 9d4c7464
......@@ -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,
......
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