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>

diff --git a/drivers/pps/generators/Kconfig b/drivers/pps/generators/Kconfig
index f3a73dd7766094641aa80a0da03751d0b5af5dfd..e4c4f3dc0728fc5c495b2283d08c180210a29379 100644 (file)
--- a/drivers/pps/generators/Kconfig
+++ b/drivers/pps/generators/Kconfig
@@ -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