Daniel,
On Fri, 2 Nov 2018, Daniel Vacek wrote:
> On Thu, Nov 1, 2018 at 4:34 PM, Thomas Gleixner <t...@linutronix.de> wrote:
> >> -#define MAX_RETRIES 5
> >> -#define SMI_TRESHOLD 50000
> >> +#define MAX_RETRIES 5
> >> +#define TSC_THRESHOLD (tsc_khz >> 5)
> >
> > This breaks pit_hpet_ptimer_calibrate_cpu() because at that point tsc_hkz
> > is 0.
>
> That did not show up with my testing, sorry. I guess
> pit_calibrate_tsc() never failed for me. Hmm, actually it looks like
> quick_pit_calibrate() does the job for me so
> pit_hpet_ptimer_calibrate_cpu() is likely not even called.
Right. It's only called when quick calibration fails. Testing does not
replace code inspection :)
> Would this:
>
> #define TSC_THRESHOLD (tsc_khz? tsc_khz >> 5: 0x20000)
>
> work for you instead? Or alternatively at some point when chasing this
> down I used:
>
> #define TSC_THRESHOLD (0x10000 + (tsc_khz >> 6))
>
> The first one seems better though. I can send v2 next week if you like it.
Can you please avoid hiding the logic in a macro? Just use a local
variable:
u64 thresh = tsc_khz ? tsc_khz >> 5 : TSC_DEFAULT_THRESHOLD;
and use that in the comparison.
Thanks,
tglx
