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SubjectRe: keyboard and USB problems (Re: 2.6.2-rc1-mm2)
On Fri, Jan 23, 2004 at 11:27:41AM -0800, john stultz wrote:
> On Fri, 2004-01-23 at 08:19, Vojtech Pavlik wrote:
> > On Fri, Jan 23, 2004 at 05:01:52PM +0100, Rudo Thomas wrote:
> > > BogoMIPS is figured out to be 8.19 (this was already reported by another user),
> >
> > ... this the root cause of the following problems.
> >
> > > and i8042.c complaints with this:
> > > i8042.c: Can't write CTR while closing AUX.
> >
> > ... bogomips is used in udelay() and that's used for waiting. If
> > bogomips is measured lower than real, the wait takes shorter and the
> > hardware doesn't do what it should in that short time.
> Well, loops_per_jiffy is actually being measured correctly as we're
> using the acpi pm timesource to time udelay(). However there is a loss
> of resolution using the slower time source, so udelay(1) might take
> longer then 1 us.

Longer udelay shouldn't cause trouble. Shorter one definitely would.

> If that is going to cause problems, then we'll need to pull out the
> use-pmtmr-for-delay_pmtmr patch. I guess our only option is then to use
> the TSC for delay_pmtrm() (as a loop based delay fails in other cases).
> I'll write that up and send it your way, Andrew.

I've seen the PM timer breaking the mouse operation rather badly in the
past, the lost-sync check was triggering for many people when the PM
timer was used. This implies time inacurracy in the range of 0.5
seconds. Could that happen somehow?

Vojtech Pavlik
SuSE Labs, SuSE CR
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