Re: ath5k: kernel timing screwed - due to unserialised register access?

[Elias Oltmanns <eo@nebensachen.de>]

Thomas Gleixner <tglx@linutronix.de> wrote:
> On Fri, 10 Oct 2008, Thomas Gleixner wrote:
>> On Fri, 10 Oct 2008, Elias Oltmanns wrote:
[...]
>> > This particular one is in
>> > drivers/net/wireless/ath5k/phy.c:ath5k_hw_noise_floor_calibration()
>> > which is called from ath5k_calibrate(), the callback executed every ten
>> > seconds in softirq context. Could this have anything to do with our
>> 
>> That makes sense. The timer expires early events are multiples of 10s
>> apart.
>
> Ok, I thought more about it and aside of the fact that the ath5k is
> doing something nasty, you unearthed a weakness in the broadcast code.
>
> Can you please try the following:
>
> Compile the acpi_processor module in to the kernel
> (CONFIG_ACPI_PROCESSOR=y) and add processor.max_cstate=1 to the kernel
> command line. If I analysed the problem correctly this will make the
> jiffies problem go away. I'm working on a fix.

Spot on, it does go away regardless whether NO_HZ or HIGH_RES are
enabled or disabled. Looking forward to testing your fix ;-).

Regards,

Elias