Messages in this thread | | | From | "Grover, Andrew" <> | Subject | RE: Incorrect mdelay() results on Power Managed Machines x86 | Date | Wed, 28 Mar 2001 15:12:01 -0800 |
| |
Sounds like the TSC makes a lousy calibration method ;-)
I know on ACPI systems you are guaranteed a PM timer running at ~3.57 Mhz. Could udelay use that, or are there other timers that are better (maybe without the ACPI dependency)?
Regards -- Andy
> -----Original Message----- > From: Pavel Machek [mailto:pavel@suse.cz] > Sent: Sunday, March 25, 2001 4:07 PM > To: Alan Cox > Cc: sfr@canb.auug.org.au; twoller@crystal.cirrus.com; > linux-kernel@vger.kernel.org > Subject: Re: Incorrect mdelay() results on Power Managed Machines x86 > > > Hi! > > > > On the ThinkPad 600E (at least), we get a Power Status > Change APM event. > > > > Any reason we couldn't recalibrate the bogomips on a power > status change, > > at least for laptops we know appear to need it (I can make > the DMI code look > > for matches there..) > > Notice that this is not 100% solution. APM is async, and you > might already > did few wrong delays by the time apm event is delivered to you. > > Also notice that at least my toshiba goes low speed (150MHz) on > *) batteries going low > *) overheat > > It goes back to 300MHz at ac power. Another crazy thing: it > goes down to > 35MHz on extreme overheat -- that's factor of 10 change. > -- > Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, > details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html. > > - > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |