Hi Alan :)
* Alan Stern <[EMAIL PROTECTED]> dixit:
> > If I remount it as read-write (as root, of course), I have
> > success and I can use the device normally, being able to write to it
> > without problems. If, instead, I manually unload sd_mod and load it
> > again, then this time the device is NOT seen as write protected (the
> > sd_mod driver says that "write protect is off").
[...]
> > The same device works OK in WinXP without any driver (well, with
> > the default USB disk driver), so I'm not sure if the problem is on
> > the device (in fact, it works OK after remounting "rw" by hand or
> > manually reloading sd_mod) or in the kernel drivers (which I find
> > very unlikely, since similar Inovix players work as-is).
>
> This does not sound like a problem with the USB stack.
I first thought that the problem was a faulty USB device, but the
device works OK under WinXP and MacOS (this one not tested by myself
but by a friend, so I cannot provide details), only Linux has
problems. Obviously, the device is sending incorrect data because if
it is polled twice, the second time it will correctly regarded as non
write protected.
> You can find out for certain what's really happening by using the usbmon
> facility in 2.6.17. Instructions are in the kernel source file
> Documentation/usb/usbmon.txt.
I don't have right now a 2.6.17 kernel running nor a machine I
can test new kernels on, but I'll try my best to do it, thanks a lot
:)
> My best guess at this point is that the device sometimes sends
> incorrect information about the write-protect setting back to the
> computer.
Yes, that seems to be true, but the question is: why? And why
other OSes doesn't have problems with it? Do the rest of OSes poll
repeteadly the device or do they just ignore the read-write status of
the device?
Well, thanks a lot for your interest, Alan. As soon as I can test
a 2.6.17 kernel with usbmon enabled I'll do for sure. Probably next
week I'll get a handheld with a 2.6.17 kernel and I'll be able to
carry some tests :))
I didn't know about usbmon, so thanks a lot for pointing.
Raúl Núñez de Arenas Coronado
--
Linux Registered User 88736 | http://www.dervishd.net
http://www.pleyades.net & http://www.gotesdelluna.net
It's my PC and I'll cry if I want to... RAmen!
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