Re: USB storage SCSI EH oops

Linus Torvalds
2012-04-14T22:49:24Z

On Sat, Apr 14, 2012 at 3:29 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Confirmed.
>
> I tested twice: with that patch, the oops is repeatable, and happens
> something like 30 seconds after plugging in the USB thing into the
> monitor.
>
> With that patch reverted, the thing still doesn't *work*, but I don't
> get the oops. Instead, I get the appended noise in my dmesg..

.. and the reason that card reader has trouble seems to be that it's
just too damn old, and doesn't understand SD-HC cards. It works fine
with old SD cards.

So the reader is fine (well, apart from being too old), USB-storage is
fine, but the SCSI error handler is broken.

Even with that commit reverted, once the SCSI layer has decided to
off-line the device, you can't get it back, even if you remove the
media and insert a non-HC SD card. You have to unplug and re-plug the
reader. That seems to be a slight misfeature of SCSI error handling,
but compared to oopsing, it's minor.

Linus