pps: make pps_gen_parport depend on BROKEN

This driver causes hard lockups, when the active clock soure is jiffies.

The reason is that it loops with interrupts disabled waiting for a
timestamp to be reached by polling getnstimeofday().  Though with a
jiffies clocksource, when that code runs on the same CPU which is
responsible for updating jiffies, then we loop in circles for ever
simply because the timer interrupt cannot update jiffies.  So both UP
and SMP can be affected.

There is no easy fix for that problem so make it depend on BROKEN for
now.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: Rodolfo Giometti <giometti@linux.it>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Thomas Gleixner 2011-03-04 17:36:23 -08:00 committed by Linus Torvalds
parent 97e419a082
commit 95b90afec3

View File

@ -6,7 +6,7 @@ comment "PPS generators support"
config PPS_GENERATOR_PARPORT
tristate "Parallel port PPS signal generator"
depends on PARPORT
depends on PARPORT && BROKEN
help
If you say yes here you get support for a PPS signal generator which
utilizes STROBE pin of a parallel port to send PPS signals. It uses