Re: [3/3] 2.6.21-rc7: known regressions (v2)

[john stultz <johnstul@us.ibm.com>]

On Wed, 2007-04-25 at 04:06 -0700, Andrew Morton wrote:
> On Mon, 23 Apr 2007 23:49:09 +0200 Adrian Bunk <bunk@stusta.de> wrote:
> 
> > This email lists some known regressions in Linus' tree compared to 2.6.20.
> > 
> > If you find your name in the Cc header, you are either submitter of one
> > of the bugs, maintainer of an affectected subsystem or driver, a patch
> > of you caused a breakage or I'm considering you in any other way
> > possibly involved with one or more of these issues.
> > 
> > Due to the huge amount of recipients, please trim the Cc when answering.
> > 
> > 
> > Subject    : HPET enabled freeze my machine at boot
> >              workaround: clocksource=acpi_pm
> > References : http://lkml.org/lkml/2007/4/19/370
> > Submitter  : Guilherme Schroeder <guilherme@centralinf.com.br>
> > Caused-By  : Thomas Gleixner <tglx@linutronix.de>
> >              commit 5d8b34fdcb384161552d01ee8f34af5ff11f9684
> > Handled-By : John Stultz <johnstul@us.ibm.com>
> > Status     : problem is being debugged
> > 
> > 
> > Subject    : acpi_pm clocksource loses time on x86-64
> > References : http://lkml.org/lkml/2007/4/17/143
> > Submitter  : Mikael Pettersson <mikpe@it.uu.se>
> > Handled-By : John Stultz <johnstul@us.ibm.com>
> > Status     : problem is being debugged
> > 
> > 
> > Subject    : suspend to disk hangs  (CONFIG_NO_HZ)
> > References : http://lkml.org/lkml/2007/3/25/217
> > Submitter  : Jeff Chua <jeff.chua.linux@gmail.com>
> > Status     : unknown
> 
> That's still rather a lot of bustage from the timekeeping changes.  Is
> anything really happening here or have we all given up?


The ACPI PM one is *really* odd as its the same clocksource driver on
both arches. I had Mikael cut out the clocksource frequency adjustments,
and confirmed both i386 and x86_64 are using the same base freq
(confirmed via printks).

It almost seems like when booting x86_64 the ACPI PM counter is running
slowly! 

Len: Have you ever heard of such a thing? It seems quite unlikely...


WRT the HPET freeze issue, I'm still digging there. In that case it
appears the HPET isn't counting, so timekeeping just stops. I was
thinking it might be HRT messing w/ the wrong HPET registers, but so far
that hasn't shaken out.

I'll spend some more time on these today and see if we get any further.

thanks
-john