Re: [REGRESSION] "USB: use kfifo to buffer usb-generic serial writes"causes gobi_loader to hang

[Alan Stern]

On Mon, 22 Feb 2010, Anssi Hannula wrote:

> > > If I additionally insert a one-second delay before the fd is closed, I
> > > get this usbmon log:
> > > http://stuff.onse.fi/gobi2000/gobi-regression5.mon.log
> > > 
> > > The firmware upload is still unsuccessful.
> > 
> > If I use the option driver instead of qcserial, the firmware upload is
> > always successful (without any added delays needed). The usbmon log for
> > that case can be found here:
> > http://stuff.onse.fi/gobi2000/gobi-regression6.mon.log
> 
> I installed 2.6.31.12 to get a usbmon log with qcserial before the regression 
> as well (without delays, upload successful):
> http://stuff.onse.fi/gobi2000/gobi-regression7.mon.log

The major difference between the logs is in the way the data get
divided up into packets.  In both the successful logs, there are 
sequences of bulk-OUT packets with lengths like:

	44, 1, 15, 1, 13

where the unsuccessful transfer just has a single packet of length 74.  
Also, the successful transfers show a lot of bulk-IN traffic where the 
unsuccessful transfer doesn't have any.  I don't know if that is 
relevant, however.

No other differences stand out.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/