Messages in this thread | | | Date | Wed, 28 Aug 2002 10:00:33 -0700 (PDT) | From | mike heffner <> | Subject | Re: PROBLEM: conflict between apm and system clock on Inspiron 8100 |
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Hi Frank,
From your e-mail it seems that the kernel is the problem, not the bios. Is that your understanding? I started pestering Dell for a bios without this problem. Should I be digging through the kernel code instead?
Mike
--- Frank.Otto@tc.pci.uni-heidelberg.de wrote: > Alan Cox wrote: > > On Mon, 2002-08-26 at 18:00, mike heffner wrote: > > > Well, isn't that a nice feature. Is there a > > > workaround for this hardware? > > > > A thinkpad ;) > > Unfortunately, that's not true -- I just got an IBM > Thinkpad R32 > which exhibits the same behaviour as Mike's Dell > Inspiron 8100, > it's only a tad worse. When I have the > battstat_applet running (which > checks the battery every second), kernel time runs > about 3% slow > compared to the RTC (which seems to be half-way > accurate on my machine). > > The cause seems to be definitely APM. If I shut off > battstat_applet > and apmd, kernel time and RTC are in sync. With only > apmd, I lose about > 15 seconds per hour. With battstat_applet, I lose 2 > minutes per hour. > With > while true; do cat /proc/apm >/dev/null; done > the system runs at about 1/4 of the right speed. > Using a kernel with ACPI > eliminates the problem (of course, you lose almost > all power management > functionality too). > > BTW, I have set CONFIG_APM_ALLOW_INT, and on startup > the kernel even says > "IBM machine detected. Enabling interrupts during > APM calls." Doesn't > seem to help, though. > > Alan Cox continues: > > In theory you could try writing some code to > measure the elapsed time by > > other means and then correct the kernel for the > number of lost ticks. > > Not trivial. Or for that matter dont run battstat > > I've hacked together a small daemon that tries to > adjust the value > and speed of the kernel clock (via adjtimex) to the > RTC. An ugly solution, > I know, but better than nothing. If anyone is > interested, mail me. > > Regards, > Frank > > -- > Please CC replies to me since I'm not on the list.
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