On Mon, 30 Mar 2015, Peter Chen wrote: > > That's strange. Can you please post the /sys/kernel/debug/usb/devices > > file (with the UAC2 gadget plugged in), and also collect a usbmon trace > > of the test? > > > > It should be UAC2 gadget or chipidea driver problem, it is ok if I plug > in USB audio card, but most of current audio cards support 44.1k+ > frame rate, it can't handle the 3rd endpoint (176-184 bytes / endpoint), > I don't know how to let it only read/writes 64 bytes, anyway, I will fix > the UAC2 gadget problem first. > > Device file for UAC2: > T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 14 Spd=12 MxCh= 0 > D: Ver= 0.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 > P: Vendor=15a2 ProdID=0054 Rev= 4.00 > S: Manufacturer=Freescale > S: Product=FSL i.mx6q sabreSD Board > S: SerialNumber=123456ABCDEF > C:* #Ifs= 3 Cfg#= 1 Atr=80 MxPwr= 6mA > A: FirstIf#= 0 IfCount= 3 Cls=01(audio) Sub=00 Prot=20 > I:* If#= 0 Alt= 0 #EPs= 0 Cls=01(audio) Sub=01 Prot=20 > Driver=snd-usb-audio > I:* If#= 1 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=20 > Driver=snd-usb-audio > I: If#= 1 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=20 > Driver=snd-usb-audio > E: Ad=01(O) Atr=05(Isoc) MxPS=1023 Ivl=1ms > I:* If#= 2 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=20 > Driver=snd-usb-audio > I: If#= 2 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=20 > Driver=snd-usb-audio > E: Ad=81(I) Atr=05(Isoc) MxPS=1023 Ivl=1ms This is bad. All the endpoints have maxpacket = 1023, and that's much too big for this test. We need a maxpacket size of 64 (maybe a little bigger but not much). It may be possible to test the hardware without actually plugging in a USB audio device. I can write a testing patch for ehci-hcd that will cause it to create all the appropriate siTDs and link them into the periodic schedule. All you will need is a full-speed hub. The host controller will send the isochronous packets to the hub and you should be able to watch them on a bus analyzer. There won't be any response to the packets (obviously!), but for isochronous that's okay. Does that sound like it will work? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
