Re: HPET timer broken using 2.6.23.13 / nanosleep() hangs

Dhaval Giani
2008-01-13T14:07:12Z

On Sun, Jan 13, 2008 at 08:10:46AM -0500, Andrew Paprocki wrote:
> I applied the patch to my 2.6.23.13 tree and upon reboot it stopped right after:
>
> Clocksource tsc unstable (delta = ... ns)
> Time: hpet clocksource has been installed.
>
> It locked up hard.. cursor stopped blinking and SysRq isn't working either.
>

It obviously is the wrong fix then :).

Adding a few cc's. Hopefully they will know what to do better than me.

> -Andrew
>
> On Jan 13, 2008 7:03 AM, Dhaval Giani <dhaval@linux.vnet.ibm.com> wrote:
> >
> > On Sun, Jan 13, 2008 at 06:10:52AM -0500, Andrew Paprocki wrote:
> > > I started debugging a problem I was having with my sky2 network driver
> > > under 2.6.23.13. The investigation led me to find that the HPET timer
> > > wasn't working at all, causing the sky2 driver to not work properly.
> > > Simple example:
> > >
> > > am2:/sys/devices/system/clocksource/clocksource0# cat current_clocksource
> > > jiffies
> > > am2:/sys/devices/system/clocksource/clocksource0# time sleep 1
> > > real 0m1.000s
> > > user 0m0.000s
> > > sys 0m0.000s
> > > am2:/sys/devices/system/clocksource/clocksource0# echo tsc > current_clocksource
> > > am2:/sys/devices/system/clocksource/clocksource0# time sleep 1
> > > real 0m1.005s
> > > user 0m0.004s
> > > sys 0m0.000s
> > > am2:/sys/devices/system/clocksource/clocksource0# echo hpet >
> > > current_clocksource
> > > am2:/sys/devices/system/clocksource/clocksource0# time sleep 1
> > > <hangs indefinetly...>
> > >
> > > Running strace shows it blocked on nanosleep(). I'm building the
> > > kernel with the processor type set to Athalon64. I've built it with
> > > and without SMP and high-res timers enabled and I get the same result.
> > > My previous 2.6.18-4 kernel works because it does not install HPET as
> > > the default timer. The same behavior occurs in 2.6.24-rc7 git head.
> > > I've attached the config/dmesg below.
> > >
> >
> > It seems the HPET timer was not being assigned any IRQs at all. Can you
> > try the patch at http://lkml.org/lkml/2008/1/12/128 ?
> >
> > Thanks,
> > --
> > regards,
> > Dhaval
> >
> >

--
regards,
Dhaval