Unable to make ptpcam working

[corge]

After finally getting libptp2 to compile I find that ptpcam does not work.

This has worked perfectly fine before with the same camera using Slackware 12.0, I am now using Slackware 13.1 and ptpcam will simply not work.

The error is as follows:

x86_1# ptpcam -l

Listing devices...
bus/dev vendorID/prodID device model
ERROR: Could not open session!
Try to reset the camera.

I have tried to reset with "ptpcam -r", I have also tried to disconnect and reconnect the camera to the USB system, I have tried to reboot the computer, I have tried to use different versions of libptp2 -- all to no avail.

The strace shows the issue is apparently a failed ioctl(), although I have no idea why it fails:

open("/dev/bus/usb/002/004", O_RDWR)    = 6
write(4, "\1"..., 1)                    = 1
read(3, "\1"..., 1)                     = 1
ioctl(6, USBDEVFS_SETCONFIGURATION, 0xbff18044) = 0
ioctl(6, USBDEVFS_CLAIMINTERFACE, 0xbff18014) = 0
ioctl(134577232, UI_DEV_DESTROY or USBDEVFS_BULK, 0xbff17f90) = -1 EBADF (Bad file descriptor)
write(2, "ERROR: Could not open session!\nTr"..., 56ERROR: Could not open session!
Try to reset the camera.
) = 56
ioctl(6, USBDEVFS_RELEASEINTERFACE, 0xbff18044) = 0
write(1, "\n"..., 1
)                    = 1
exit_group(0)                           = ?

I have verified that the camera is working in Windows 7 on the same physical computer and I can see the camera from lsusb and dmesg output when I connect it to the USB system.

This system is Slackware 13.1, Linux x86_1 2.6.33.4-smp #2 SMP Wed May 12 22:47:36 CDT 2010 i686 Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz GenuineIntel GNU/Linux.

[clickit]

While trying to get mplayer to work with my web cam I had similar errors after I would get it working.
Try this:
Disconnect cam and cold boot.
Run cat /proc/asound/cards and
ls /dev/au* /dev/ds* /dev/vi*
Connect cam and repeat.
Shutdown and reboot leaving cam connected
Repeat commands above.
It may be that the cards are being changed around. My cam went from card 2 to card 0. That is mystifying when it happens. Hope this solves it 4 U