I am trying to investigate an issue on a TI Sitara CPU, AM3352 with the musb USB controller.
The scenario is that a device has been in use and working correctly. The device is an Android device and is presenting as an MTP device. That first session of use is finished and the port is reset but the device is not unplugged, so enumeration and configuration starts again the next time it is needed. The transfers over EP0 using PIO all proceed as expected. The problem is the first bulk packet sent to EP1, which also happens to be the first dma packet. USBMON shows this packet as being sent. However a hardware analyser does not show this packet on the wire and of course there is no ACK either. Looking at the debug info from the musb driver I can see the dma being started and then the callback being called. MUSB_TXCSR_TXPKTRDY remains set as does MUSB_TXCSR_TXFIFONOTEMPTY so nothing else happens. The TXCSR register is 0x3403. The code is waiting for MUSB_TXCSR_TXPKTRDY to be cleared but that will not happen until an ACK is received. It just seems that the controller is not putting the packet onto the wire for some reason. This is on 4.5.1. I would welcome some pointers on how to proceed to debug this or else any information on possible applicable errata and workarounds for this. Thanks, Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
