From f167e1d073278fe231bbdd5d6c24fb9d091aa544 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 15 Feb 2010 08:55:28 +0100 Subject: 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 Cc: Signed-off-by: Jaroslav Kysela --- sound/usb/usbmidi.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/sound/usb/usbmidi.c b/sound/usb/usbmidi.c index 6e89b83..aae50df 100644 --- a/sound/usb/usbmidi.c +++ b/sound/usb/usbmidi.c @@ -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, -- cgit v1.1