serial port regression caused by "Char: tty_ioctl, use wait_event_interruptible_timeout" patch

From: Rick Warner
Date: Tue Feb 05 2008 - 14:27:44 EST


Hello all,

My company uses a proprietary hardware monitoring solution that utilizes
communication over the serial port. A RS232-RS485 converter is plugged into
the serial port of the master of a cluster, and cat5 cables are daisy chained
between the cards to handle out of band hardware monitoring. The cards
themselves speak RS485. We have been using the same software to read the
data from the serial port since the 2.4 kernel days. As of 2.6.23, the
software no longer works.

I narrowed down the problem doing a binary search on git snapshots between .22
and .23, and found the breakage between git6 and git7. Further isolating it
found the patch mentioned in the subject to be the cause. I reversed the
patch in the .23 source and it now works properly.

Should the code be reverted back as I did, or is there something I should
change in our userspace code that reads from the serial port to correct it
instead?

Thanks,
Rick

--
Richard Warner
Lead Systems Integrator
Microway, Inc
(508)732-5517
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/