Messages in this thread | | | Date | Sat, 12 Jul 2008 08:05:04 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH -tip] x86: apic LVTT - use APIC_DIVISOR on 64bit mode |
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* Cyrill Gorcunov <gorcunov@gmail.com> wrote:
> We use APIC_TDR_DIV_16 while setting APIC_TDCR (divisor) it happened > this moment is hidden from __setup_APIC_LVTT caller. So we better > increment caller 'clocks' value to not change current behaviour and > use APIC_DIVISOR (as already done in 32bit version). > > The main benefit - unified procedure code for 32/64bit modes.
> Please review carefully. Any comments are welcome. > I'm _not_ 100% sure if this patch is safe.
hm, how about the other caller to __setup_APIC_LVTT(), lapic_timer_setup():
case CLOCK_EVT_MODE_ONESHOT: __setup_APIC_LVTT(calibration_result, mode != CLOCK_EVT_MODE_PERIODIC, 1); break;
that will affect high-res timers. Wont calibration_result have the same value after your patch as well, but only a 16th of it will be used in __setup_APIC_LVTT(), causing 16 times shorter timeouts than intended?
I.e. are we fixing a bug, are we changing nothing, or are we introducing a bug? :-)
Ingo
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