> Just to make sure: on a working kernel, do you get the HPET messages?
> I.e. does the hpet truly work in that case?
On the "fileserver", where 2.6.25 works but 2.6.26 locks up, the HPET
_does_ work on a working kernel:
$ uname -r
2.6.26.revert1
$ dmesg | grep -i hpet
ACPI: HPET 77FE80C0, 0038 (r1 RS690 AWRDACPI 42302E31 AWRD 98)
ACPI: HPET id: 0x10b9a201 base: 0xfed00000
hpet clockevent registered
hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0, 0
hpet0: 4 32-bit timers, 14318180 Hz
hpet_resources: 0xfed00000 is busy
What I didn't realize is that the "desktop" machine, where 2.6.26 has
always "worked", does NOT have a working HPET after all, even though
I have enabled all HPET options in .config:
$ uname -r
2.6.26.080801.desktop.uvesafb
$ dmesg | grep -i hpet
$
This means I misunderstood my situation on "desktop". I believed HPET
was working on all of my machines, but now I am not certain that it
ever worked on "desktop" since I built it (May 2007). The question
never arose before, and because I enabled the HPET option in .config,
I just assumed that HPET was working. (Duh...) I failed to look into
this until now.
At any rate, my subject line is still accurate: there _is_ an HPET
regression on "fileserver" (and "webserver"), since it worked on
2.6.25 kernels but causes lockups on 2.6.2[67] kernels.
(I don't know what is going on with "desktop": does the motherboard
lack HPET, or does the Linux kernel not support the HPET hardware on
the motherboard?)
BTW: the 'dmesg' output above is the same on "desktop" with 2.6.25
and 2.6.26 -- I just checked to be sure. For "fileserver", I checked
an old 2.6.25 kernel just now, and the output is identical.
Another experiment: I just tried this...
static __init int hpet_insert_resource(void)
{
- if (!hpet_res)
+ /* if (!hpet_res) */
return 1;
- return insert_resource(&iomem_resource, hpet_res);
+ /* return insert_resource(&iomem_resource, hpet_res); */
}
... and the lock up still occurs. So, the memory is allocated but
the resource info is not inserted into the tree. Whether the
dynamic memory for hpet_res is being damaged or not has no bearing
on the lockups, it would seem. Looks like I was barking up the
wrong tree....
Dave W.
* David Witbrodt <[email protected]> wrote:
> > Just to make sure: on a working kernel, do you get the HPET
> > messages? I.e. does the hpet truly work in that case?
>
> On the "fileserver", where 2.6.25 works but 2.6.26 locks up, the HPET
> _does_ work on a working kernel:
>
> $ uname -r
> 2.6.26.revert1
>
> $ dmesg | grep -i hpet
> ACPI: HPET 77FE80C0, 0038 (r1 RS690 AWRDACPI 42302E31 AWRD 98)
> ACPI: HPET id: 0x10b9a201 base: 0xfed00000
> hpet clockevent registered
> hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0, 0
> hpet0: 4 32-bit timers, 14318180 Hz
> hpet_resources: 0xfed00000 is busy
btw., you might also want to look into drivers/char/hpet.c and
instrument that a bit. In particular the ioremap()s done there will show
exactly how the hpet is mapped.
In particular this bit:
if (hpet_is_known(hdp)) {
printk(KERN_DEBUG "%s: 0x%lx is busy\n",
__func__, hdp->hd_phys_address);
iounmap(hdp->hd_address);
return AE_ALREADY_EXISTS;
}
suggests that you've got multiple hpets listed by the BIOS?
> What I didn't realize is that the "desktop" machine, where 2.6.26 has
> always "worked", does NOT have a working HPET after all, even though I
> have enabled all HPET options in .config:
that's OK - you've still got a regression.
> (I don't know what is going on with "desktop": does the motherboard
> lack HPET, or does the Linux kernel not support the HPET hardware on
> the motherboard?)
Whether the system has a hpet listed in the BIOS data structures can be
seen in acpidump [in the pmtools package]
Even if the BIOS does not list it, the system might have hpet in the
chipset - hpet=force can be tried to force-enable it.
Ingo