[sane-devel] Mustek BP 1200 CU PLUS / Bug

[Henning Meier-Geinitz]

Hi,

On 2006-01-18 00:08, Lorenzo Delana wrote:
> I have a Mustek BP 1200 CU PLUS scanner A4, that /proc/bus/usb/devices 
> describe as:

I have the same scanner and it works flawlessly. Also many others use
this scanner.

> 1) I installed cvs version of sane-backend and when I use scanimage the 
> problem go in Segmentation Fault;
> to solve this I have to add a NULL POINTER check on the line 461 of the code 
> so that:

I assume this is in sanei/sanei_usb.c?

> -------------
> 	case USB_CLASS_PER_INTERFACE:
> 		  if (dev->config[0].interface[interface].altsetting)
> 		  switch (dev->config[0].interface[interface].altsetting[0].
> 			  bInterfaceClass)
> 		    {
> ----------------
> This because altsetting something got me a NULL, then altsetting[0] is 
> dereferencing a null pointer.

How can altsetting[0] be 0? This means that an interface exists but no
altsetting. I'm not that used to the USB spec but I would be surprised
if this is allowed. Anyway, if your scanner does this, it can't scan
because it's broken. I rather assume that it happens with some other
device connected to your USB. Could you try to find out which device
behaves this way? And please send a log with USB debugging enabled:
SANE_DEBUG_SANEI_USB=255 scanimage -L

As an alernative to a strangely acting device, there could be a
problem with libusb. However, this is the first time I hear about such
trouble.
 
I'll add some checks for altsetting !=0 to sanei_usb as they don't
harm. But I think the problem is somewhere else.

> 3) as for 1) in tools/sane-find-scanner.c at line 627

Could you send the output of "sane-find-scanner -v -v", please?
 
> 4) at backend/gt68xx_high.c
> I have commented out the check for the status, because in this point the 
> program blocks forever ( for my scanner ). changing status = SANE_STATUS_GOOD
> for quickly replacement.
 
Which status exactly? Which line of the code? Please send a log file
of a scan where it blocks (without your change).

Bye,
  Henning