On Mon, 8 Dec 2003, Ethan Mattor wrote: > Problem 2) > The amount of returned descriptor is a bit touchy. As far as I can tell, by > the USB specification, when the host asks for 'x' number of bytes through > the wLength field, the device is expected to return a payload of 'x' of > bytes during the data phase. However, in practice this does not work as > expected. First, when the host requests the first 8 bytes of the device > descriptor, it hangs and reports a CRC error. Funny enough, it has actually > received all 8 bytes expected, but still the UHCI silicon generates a > CRC/Timeout error: > > <7>drivers/usb/host/uhci-hcd.c: 1800: wakeup_hc > <7>hub 1-0:1.0: debounce: port 2: delay 100ms stable 4 status 0x101 > <6>hub 1-0:1.0: new USB device on port 2, assigned address 17 > <4>usb 1-2: control timeout on ep0in > <4>usb 1-2: actual length = 0 > <7>drivers/usb/host/uhci-hcd.c: uhci_result_control() failed with status > 440000 <4>[c5363240] link (053631e2) element (0532e100) > <4> 0: [c532e100] link (0532e140) e0 Stalled CRC/Timeo Length=7 MaxLen=7 DT0 > EndPt=0 Dev=11, PID=2d(SETUP) (buf=0ad312c0) > <4> 1: [c532e140] link (0532e180) e3 SPD Active Length=0 MaxLen=7 DT1 > EndPt=0 Dev=11, PID=69(IN) (buf=069a8364) > <4> 2: [c532e180] link (00000001) e3 IOC Active Length=0 MaxLen=7ff DT1 > EndPt=0 Dev=11, PID=e1(OUT) (buf=00000000)
The CRC/Timeout error is for the SETUP packet. This means that the device didn't send an ACK in response to the SETUP as it was obliged to do. Or if it did send one, the ACK got mangled somehow. According to this log trace the host never did send the IN packet asking for the device to transmit its 8 bytes. So what makes you think the device sent them? And if the device did send them, why did it send them without being asked to do so? Alan Stern ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
