[Please Cc on reply] Hi,
I recently bought an USB MIDI interface from ESI (called “ESI MIDI Mate”). It claims to work with Linux, but doesn't -- I've already asked the manufacturer for an explanation, but as I was impatient, I hacked a bit on the drivers to actually make it work... The /proc/bus/usb/devices entry looks like this: T: Bus=04 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 4 Spd=1.5 MxCh= 0 D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1 P: Vendor=0a92 ProdID=1001 Rev= 1.04 S: Manufacturer=ESI S: Product=ESI MIDI Mate C:* #Ifs= 2 Cfg#= 1 Atr=80 MxPwr= 20mA I:* If#= 0 Alt= 0 #EPs= 0 Cls=01(audio) Sub=01 Prot=00 Driver=snd-usb-audio I:* If#= 1 Alt= 0 #EPs= 2 Cls=01(audio) Sub=03 Prot=00 Driver=snd-usb-audio E: Ad=81(I) Atr=02(Bulk) MxPS= 4 Ivl=0ms E: Ad=01(O) Atr=02(Bulk) MxPS= 4 Ivl=0ms There are two points worth noting here: - The device is USB low speed. snd-usb-audio simply checks for full/high speed, and refuses any device that isn't. I can hack around this, inverting a few checks etc., and it seems to work reasonably well (probably since the device has no PCM parts). - Both endpoint descriptors are bulk. The HCD driver plain refuses bulk transfers for low-speed; it looks like they are disallowed in the USB standard somehow. If I comment out the check, the driver works (perfectly!), but I guess this isn't acceptable for upstream? Could the check for low-speed bulk transfers be replaced by a kernel warning somehow? I can't see any big harm by allowing them, and obviously, Windows XP and Mac OS X does so. I can supply a patch for the snd-usb-audio specific parts if desired, but I can't guarantee it's the correct fix for cards that support PCM. Not that I know of any PCM-capable low-speed USB sound cards out there... /* Steinar */ -- Homepage: http://www.sesse.net/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
