On Fri, Apr 28, 2006 at 09:56:26AM -0400, Alan Stern wrote:
> On Thu, 27 Apr 2006, Marc Singer wrote:
> 
> > I may have been a little hasty.  This new driver *does* work properly
> > on the lh79524.  It still fails test 14 on the lh7a404.  I am now very
> > suspicious that this is a hardware issue and not a software error.
> > 
> > In a nutshell, on receipt of some ep0 OUT messages, I see all of the
> > packets from the host including the short packet that completes the
> > read.  I clear the packet ready and set the DATA_END bits and wait for
> > a new message.  The host never sends one.  It reports on overflow
> > which I assume means that it didn't get the response it expected.
> > 
> > This doesn't happen all of the time.  I may have as many as 220
> > exchanges in test 14 before one of the transfers fails.
> > 
> > Once I fixed a race, the lh79524 controller works fine with the driver
> > as is.
> > 
> > Below is dmesg output from the host.
> > 
> >   usbtest 2-2:3.0: TEST 14:  15000 ep0out, 1..256 vary 1
> >   uhci_hcd 0000:00:1d.1: uhci_result_control: failed with status 500000
> >   [ef0e1180] link (2f0e1142) element (1c145300)
> >    Element != First TD
> >     0: [dc145000] link (1c145030) e3 Length=7 MaxLen=7 DT0 EndPt=0 Dev=2c, 
> > PID=2d(SETUP) (buf=2e823a00)
> >     1: [dc145030] link (1c145060) e3 Length=7 MaxLen=7 DT1 EndPt=0 Dev=2c, 
> > PID=e1(OUT) (buf=2395d6c0)
> >     2: [dc145060] link (1c145090) e3 Length=7 MaxLen=7 DT0 EndPt=0 Dev=2c, 
> > PID=e1(OUT) (buf=2395d6c8)
> >     3: [dc145090] link (1c145180) e3 Length=7 MaxLen=7 DT1 EndPt=0 Dev=2c, 
> > PID=e1(OUT) (buf=2395d6d0)
> >     4: [dc145180] link (1c1451e0) e3 Length=7 MaxLen=7 DT0 EndPt=0 Dev=2c, 
> > PID=e1(OUT) (buf=2395d6d8)
> >     5: [dc1451e0] link (1c145240) e3 Length=7 MaxLen=7 DT1 EndPt=0 Dev=2c, 
> > PID=e1(OUT) (buf=2395d6e0)
> >     6: [dc145240] link (1c1452a0) e3 Length=7 MaxLen=7 DT0 EndPt=0 Dev=2c, 
> > PID=e1(OUT) (buf=2395d6e8)
> >     7: [dc1452a0] link (1c145300) e3 Length=2 MaxLen=2 DT1 EndPt=0 Dev=2c, 
> > PID=e1(OUT) (buf=2395d6f0)
> >     8: [dc145300] link (00000001) e3 IOC Stalled Babble NAK Length=7ff 
> > MaxLen=7ff DT1 EndPt=0 Dev=2c, PID=69(IN) (buf=00000000)
> > 
> >   usbtest 2-2:3.0: ctrl_out, wlen -75 (expected 51)
> > 
> > It is odd to me that this list shows 7 byte packets when the target is
> > reading 8 byte packets.  In both cases, the byte totals are 51.
> 
> What you don't realize is that the UHCI hardware stores the packet length
> - 1, not the length itself.  So the first seven packets above actually are
> 8 bytes long, the second to last is 3 bytes (total 59), and the last --
> which constitutes the status stage of the control transfer -- is supposed
> to have length 0.  The fact that the device is sending back more than 0
> bytes is what causes the overflow error.

Are the extra bytes framing?  You can see that even usbtest thinks
this is a 51 byte message.

Where is the part where the device is sending back more than zero
bytes?  Are you talking about line 7?


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