[linux-dvb] Re: Nova-T 500 (dvb_usb_dib0700) usb disconnects

Antti P Miettinen ananaza at iki.fi
Tue Feb 27 21:13:59 CET 2007


> It seems that the XactErr bit gets set occasionally but does
> not always lead to hard failure:

But then it seems that eventually it occasionally does:

[17182959.448000] ehci_hcd 0000:03:0c.2: XactErr, token=0000cd08
[17186270.500000] ehci_hcd 0000:03:0c.2: XactErr, token=00004d08
[17192204.628000] ehci_hcd 0000:03:0c.2: XactErr, token=00004d08
[17207488.564000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17207534.812000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17210149.544000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17213184.564000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17234794.928000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17269865.128000] ehci_hcd 0000:03:0c.2: XactErr, token=00004d08
[17289071.784000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17290546.404000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17293014.016000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17293428.860000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17293474.040000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17298119.660000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17299546.240000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17300465.852000] ehci_hcd 0000:03:0c.2: XactErr, token=80004d08
[17300788.188000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17300925.768000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17300972.004000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17301063.372000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17301155.772000] ehci_hcd 0000:03:0c.2: XactErr, token=8000cd08
[17301248.172000] ehci_hcd 0000:03:0c.2: XactErr, token=8038c948
[17301248.172000] ehci_hcd 0000:03:0c.2: XactErr, token=a8002148
[17301248.172000] ehci_hcd 0000:03:0c.2: devpath 1 ep3in 3strikes,t=a8002148

The last transaction error has also the Halted bit set for the
status field of the token. The EHCI spec says: "This can be caused by
babble, the error counter counting down to zero, or reception of the
STALL handshake from the device during a transaction.". The "Babble
Detected" bit is not set whereas the CERR is zero (but that we knew
already from the 3strikes debug print). The previous transaction error
has CERR==2, but there's no transaction error with CERR==1.. hmm..

Also the other transaction errors have all CERR==3 and transfer length
of zero.

I put the usbmon log to

  http://www.hut.fi/~apm/usb-disconnect3.txt.gz

If my reasoning about the timestamps is correct the last transaction
error is at timestamp 30344747. There is a transfer length 10240 at
that timestamp which would match the token value a8002148.

I suppose I'll go reading the USB2 spec now.. :-)

-- 
http://www.iki.fi/~ananaza/




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