On Tue, 30 Nov 2004, Andrea Pusceddu wrote:

> I installed and compiled the 2.6.9 kernel, according to your hint.
> Actually the SIGMATEL 0x66f  0x8000 device is listed , and uses a
> US_FL_FIX_CAPACITY switch. Nonetheless, I keep on having errors, and I
> can't mount it.
> Trying to do my best without having to bother you, I changed the bcd
> min max from (0x0001, 0x0001) to (0x0000, 0xfffff) because, if I
> understand correctly these parameters are the min and max firmware
> version allowed to use that switch,and I guessed that my firmware
> could have a version number different from the one reported.
> No luck as well, unfortunately :(

You can find out the revision number embedded in your device by checking 
/proc/bus/usb/devices.  It's also in the 2.6.9 log, where the value shows 
up as 0x1000.  So changing the bcd max was a good idea, although it may 
not address the actual problem.

> I'm attaching the foollowing information
> 
> 
> 1) 2.6.9 dmesg output (usb storage debug switch on) 
> 
> 2) 2.6.8 dmesg output from kernel 2.6.8 (debug on)  with usb patch
> (https://bugzilla.ubuntu.com/show_bug.cgi?id=3479) and with the proper
> unusual dev entry taken from 2.6.9.
> I'm including also this file because IMHO is much clearer than the
> 2.6.9 one, in which I had a massive amount of output, that didn't fit
> in the first dmesg command. I did a couple of different dmesg dumps
> and merged the files.

Yes, unfortunately there was too much output under 2.6.9 and the important 
information was lost.  Never mind; it looks like the 2.6.8 log will be 
good enough.

> Strangely in the 2.6.8 kernel, dmesg shows the correct device name
> string, whereas in the 2.6.9  it's only shown vendor and device id ,
> and the name string is a generic <USB PRODUCT>

That's because the place where you see those values in the 2.6.9 log is 
after the device firmware has already died.  The name string must be some 
default stored by the OEM, to be used when the custom information for the 
actual reseller isn't available.

> Frankly, I'm kind of embarassed in asking your support like you was an 
> helpdesk,
> and I *do* guarantee you that I did my best in trying to find on the
> web a way to fix
> things myself, before asking. I RTFM all over the web :)

Don't worry about asking for help; it's a large part of what I do.

>From the 2.6.8 log, it looks like your device has a problem with the 
PREVENT/ALLOW MEDIUM REMOVAL command.  It failed and so did everything 
following.  You can suppress those commands by following this procedure: 
Before plugging in the device, make sure the scsi_mod driver is loaded (if 
you modprobe usb-storage, it will bring in scsi_mod along with it).  Then, 
as root, do

        echo 'SigmaTel:MSCN:0x80400' >/proc/scsi/device_info

That should work with both 2.6.8 and 2.6.9.  If it does work, we can
modify the kernel so that later versions will know about this
automatically.  Let me know what happens.

Alan Stern



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