[nSLUG] Re Card Reader

Aaron Spanik a.spanik at ns.sympatico.ca
Sun Feb 10 22:28:29 AST 2008

On Sun, 10 Feb 2008 14:28:49 -0400
Rich <budman85 at eastlink.ca> wrote:

> William Marchant wrote:
> > Hi,
> > 	I bought a 4GB card for my camera, and discovered that the card reader
> > in my laptop would not read it.  However, the card came with a usb
> > adapter.  The card works fine with the adapter.
> > 	The answer is that the computer's card slot is SDMS, and the card that
> > came with the camera is also.  The new card is SDHC. SDMS slots cant
> > touch it, hence the usb adapter.
> >
> Yup, buy only card readers after Jan 2007, I think that was the date for 
> SDHC spec.
> Watch what readers you buy and that they state SDHC. 
> Good news, I sent it into the kernel bug watch and its labeled as a bug 
> for the ub driver.
> They are working on a patch as we speak. :)  woohoo my first bug report.

It might just be that there wasn't enough information in your initial
email, but I'm quite confused by this.

The log lines you posted were:

> usb 2-1: USB disconnect, address 5
> usb 2-1: new full speed USB device using uhci_hcd and address 6
> usb 2-1: configuration #1 chosen from 1 choice
>  uba: uba1
> usbcore: deregistering interface driver usb-storage
> Initializing USB Mass Storage driver...
> usbcore: registered new interface driver usb-storage
> USB Mass Storage support registered.
> FAT: bogus number of reserved sectors
> VFS: Can't find a valid FAT filesystem on dev uba

The "USB Mass Storage support registered." apparently comes
from /usr/src/linux/drivers/usb/storage/usb.c (at least on my OpenSUSE
10.3 system running kernel 2.6.22), which is the usb-storage.ko kernel
module.  The usb-storage.ko module, to my knowledge, links into the
SCSI layer in the kernel, which generally assigns devices like /dev/sd?
to USB disk devices as well as SCSI disk devices.

The output above specifies /dev/uba, though, and you specify that the
problem has been labelled a bug in the ub driver, which I assume
indicates ub.ko, also known as the "Low Performance USB Block Driver."
The ub driver, according to the link posted by Mike Spencer in
another post (http://gentoo-wiki.com/HOWTO_USB_Mass_Storage_Device), is
to be avoided if at all possible.

Do you have both the ub and usb-storage drivers built-in or loaded
simultaneously as modules in your system?  There is apparently also
something called "libusual" which can mitigate runtime conflicts
between ub and usb-storage, which implies that the two tend to conflict.

With udev and hal in the mix, it may be that your system can't use
usb-storage.ko for the device, so ub.ko is being loaded.  Or it may be
that udev is set to name all USB Storage Devices, regardless of driver,
to /dev/ub?.  

Anyways, more grist for the mill; I'm curious how it all shakes out.


Aaron Spanik
a.spanik at ns.sympatico.ca

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