[cups.bugs] tcgetattr() causes lockup in USB backend on FreeBSD6-STABLE

[Eygene Ryabinkin]

Peter, good day.

Thu, May 03, 2007 at 05:06:13PM +0200, Peter van Heusden wrote:
> Sorry, a bit more investigation revealed that my earlier comments were
> wrong. Yes, the tcgetattr() call *does* "hang" - on my system it takes
> 10 seconds to return, before returning ENODEV (the only thing that ioctl
> on a ulpt returns on FreeBSD, according to my reading of the kernel).
> That, however, isn't the real problem - the real hang occurs when
> backendRunLoop() in runloop.c tries to read backchannel data from the
> ulpt - despite select() saying that there is data available, the read()
> blocks (I've even tried making the read buffer's size 1 byte, the
> problem persists). This causes the usb backend hang. So indeed, setting
> use_bc = 0 solves the problem. I'm not sure why select() / read()
> interact like this.

Seems like the FreeBSD kernel reports your device as the bi-directional
one? I mean that 'dmesg | grep directi' shows something like 'ulpt0:
using bi-directional mode'? If yes, then adding your device to the
USB quirks as the uni-directional one should fix your problem.

If you can rebuild the kernel, but don't know how to correct the
quirks, send me the output of the 'usbdevs -v' with the printer
plugged in and I will try to send you the patch for the USB quirks
file.
-- 
Eygene