On Thu, 11 Jul 2013, Victor Yeo wrote: > Thanks. The USBCV test has tight timing requirement. Once Set-Config > request is sent out, USBCV sends out Get-Config request to get the > config value immediately. At that time, gadget driver has not yet done > the handle_exception. So Get-Config request returns old config value, > and USBCV declares the test failed. Please see the log below. > > Is there any way to speed up the handle_exception No. > or to ask the USBCV > host to not send out Get-Config immediately? I am not at all familiar with USBCV, but I doubt it. However, the USB-2 spec says (section 9.2.6.4) that devices should be able to carry out requests with no Data stage (such as Set-Config) within 50 ms. Does your gadget really take longer than that to handle the exception? To find out, collect a usbmon trace showing what happens when your new driver is plugged into a Linux host. > I have set the NAK and > stall the endpoint 0 after receiving Set-Config request, however, That doesn't make sense. Stalling the endpoint means sending a STALL packet. You can't send both a STALL and a NAK. > Get-Config request is still sent out by USBCV host immediately. There should be at least a 50-ms delay, unless the UDC driver is doing something wrong. 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
