On 2019 Feb 21 (Thu) at 16:19:22 +0100 (+0100), Patrick Wildt wrote: :On Thu, Feb 21, 2019 at 03:56:57PM +0100, Stefan Sperling wrote: :> On Thu, Feb 21, 2019 at 10:50:40AM +0100, Patrick Wildt wrote: :> > Hi, :> > :> > on my i.MX8M machine which features a DWC3 xHCI 1.10 controller I have :> > seen this error while installing base64.tgz or running fsck: :> > :> > umass0: Invalid CSW: sig 0x43425355 should be 0x53425355 :> > :> > As it turns out using a USB protocol analyzer, the transfers actually :> > seem fine, the USB mass storage is not responding nonsense. By further :> > looking into it I realized that our xhci(4) is told the transfer was :> > completed, even though the buffer had not been touched. :> > :> > Further debugging revealed that the issue occured when a transfer that :> > spans multiple TRBs loops over the ring. This means one TRB is using :> > idx 254, the next TRB is the link TRB which does not contain data and :> > sits at idx 255, and the following data TRB is using idx 0. :> > :> > Transfers that comprise of multiple TRBs must have the chain bit set in :> > all but the last TRB. Now in this case the link TRB which sits in the :> > middle does not get the chain bit set, and thus processing stops. :> > :> > Somewhere I have seen code that always sets the chain bit in the link :> > TRB, so I'm wondering if we should follow that too. For now I think the :> > easiest fix for this is to set the chain bit in the link TRB if the :> > transfer spans multiple TRBs. :> > :> > Feedback? :> :> Is this why the #if 0 isochronous transfer code doesn't work? :> : :That's possible. Do you have a device you could test this with? :
tested here with uvideo0: xhci0 at pci0 dev 20 function 0 "Intel 100 Series xHCI" rev 0x21: msi, xHCI 1.0 usb0 at xhci0: USB revision 3.0 uhub0 at usb0 configuration 1 interface 0 "Intel xHCI root hub" rev 3.00/1.00 addr 1 ... uvideo0 at uhub0 port 8 configuration 1 interface 0 "Chicony Electronics Co.,Ltd. Integrated Camera" rev 2.00/0.06 addr 3 video0 at uvideo0 ... xhci0: NULL xfer pointer xhci0: wrong trb index (4227450112) max is 255 xhci0: wrong trb index (4227450112) max is 255 xhci0: NULL xfer pointer -- Q: How many Martians does it take to screw in a lightbulb? A: One and a half.
