On Fri, Sep 28, 2012 at 11:39:48AM -0400, Alan Stern wrote: > On Fri, 28 Sep 2012, Don Zickus wrote: > > > > Probably the device was already hung. The log showed that an earlier > > > transfer completed with a STALL. The reason wasn't apparent, although > > > a usbmon trace might give a clue. It might also show why the device > > > had to be reset. > > > > Here is the output of 'cat 4u' > > > ffff880240121860 3207118259 S Bo:4:002:3 -115 31 = 55534243 6c000000 00000000 00000600 00000000 00000000 00000000 000000 > > ffff880240121860 3207118359 C Bo:4:002:3 0 31 > > > ffff880240121860 3207118430 S Bi:4:002:4 -115 13 < > > ffff880240121860 3207118511 C Bi:4:002:4 0 13 = 55534253 6c000000 00000000 00 > > ffff880240121860 3207127088 S Bo:4:002:3 -115 31 = 55534243 6d000000 00020000 80000ca1 082e0001 00000000 ec000000 000000 > > ffff880240121860 3207127197 C Bo:4:002:3 0 31 > > > ffff880240122698 3207127238 S Bi:4:002:4 -115 512 < > > ffff880240122698 3207143925 C Bi:4:002:4 -32 0 > > ffff880240121860 3207144021 S Co:4:002:0 s 02 01 0000 0084 0000 0 > > ffff880240121860 3207220654 C Co:4:002:0 -32 0 > > ffff880240122698 3207220814 S Co:4:001:0 s 23 03 0004 0004 0000 0 > > ffff880240122698 3207226644 C Co:4:001:0 0 0 > > This shows that the problem began when the device was sent a command it > didn't recognize: 0xA1, which is a 12-byte ATA pass-through, in this > case for an IDENTIFY DEVICE command (0xEC). Presumably the Western > Digital device doesn't support ATA pass-through. The device halted its > bulk-IN endpoint and then replied with a STALL to the > Clear-Endpoint-Halt request (which is an invalid response). This is > why the reset was tried. > > Don, what does a comparable usbmon trace look like when the drive is > attached to an EHCI controller? I would expect to see basically the > same thing. I can grab that. I just wanted to note that this drive works fine under a Fresco Logic or NEC xhci controller. But those controllers don't seem to invoke the LPM code paths either. I'll provide an EHCI usbmon trace from the panther point controller and if interesting a usbmon trace from an NEC xhci controller. Cheers, Don -- 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
