Jan Kiszka wrote:
> Hi,
>
> just checked on real hardware (found in qemu originally):
>
> When Linux uses the pit clocksource AND Xenomai is attached, the system
> time no longer makes progress. Observed under 2.6.20 with 1.7-03 and
> newer patches, Xenomai trunk.
>
> I guess not many people will be affected by this and I'm lacking time to
> debug, so I'm just dumping the report and running away...
Somehow I hate open issues...
I recalled some private thread with you, Philippe, about this particular
line in pid_read(). A look at it again revealed the reason for this bug.
Jan
PS: pending_patches++ ;)
---
arch/i386/kernel/i8253.c |3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-2.6.20/arch/i386/kernel/i8253.c
===
--- linux-2.6.20.orig/arch/i386/kernel/i8253.c
+++ linux-2.6.20/arch/i386/kernel/i8253.c
@@ -47,7 +47,8 @@ static cycle_t pit_read(void)
#ifdef CONFIG_IPIPE
if (!__ipipe_pipeline_head_p(ipipe_root_domain))
- return 0; /* We don't really own the PIT. */
+ /* We don't own the PIT, fall back to jiffies. */
+ return (cycle_t)(jiffies * LATCH);
#endif /* CONFIG_IPIPE */
spin_lock_irqsave(&i8253_lock, flags);
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