On Wed, 17 Apr 2013, victor yeo wrote: > Hi, > > >> From the usbmon trace and driver log, i can only see that TEST UNIT > >> READY command is sent out but UDC driver does not receive it. May i > >> ask, under what circumstances, is gadget driver calling > >> start_transfer() to schedule reading from bulk-out endpoint ? > > > > file_storage.c calls start_transfer() whenever it expects the host to > > send a bulk-out packet. These times include: > > > > When the gadget is waiting for the host to send a CBW packet > > containing a SCSI command; > > I think the get_next_command() calls start_transfer() to read the next > CBW. After unknown command 0xa1 is received, and if UDC driver doesn't > halt the endpoint, why the get_next_command() does not call > start_transfer() to read the next CBW? Somehow, i don't understand. I think that the previous call to start_transfer() never returned. Probably because the usb_ep_queue() routine got hung up. Therefore get_next_command() wasn't executed. Here's an extract from the log you posted, showing the 0xa1 command: > [start_transfer] f 40a08 > ept1 out queue len 0x200, buffer 0xc12ac000 > g_file_storage gadget: bulk-out, length 31: > 00000000: 55 53 42 43 12 00 00 00 00 02 00 00 80 00 0c a1 > 00000010: 08 2e 00 01 00 00 00 00 ec 00 00 00 f8 9e 34 > bulk_out_complete --> 0, 31/31 > g_file_storage gadget: SCSI command: Unknown xa1; Dc=12, Du=0; Hc=12, Hi=512 > g_file_storage gadget: bulk-in, length 0: > [start_transfer] 43425355 12 > ept1 in queue len 0x0, buffer 0xc12ac000 > g_file_storage gadget: bulk-in set halt > kagen2_set_halt 1 1 > g_file_storage gadget: sending command-failure status > g_file_storage gadget: sense data: SK x05, ASC x20, ASCQ x00; info x0 > g_file_storage gadget: bulk-in, length 13: > 00000000: 55 53 42 53 12 00 00 00 00 02 00 00 01 > [start_transfer] 53425355 12 > ept1 in queue len 0xd, buffer 0xc133c000 > 0: 0x53425355 > 4: 0x12 > 8: 0x200 It looks like the UDC driver get hung up right here, somewhere inside the usb_ep_queue() routine. > bulk_in_complete --> 0, 13/13 > ka2000_ack_irq(32) > ka2000_ack_irq(32) > g_file_storage gadget: disconnect or port reset At this point, the host got tired of waiting for the gadget to accept the next CBW, so it issued a port reset. 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
