Messages in this thread | | | Date | Wed, 11 Jun 2008 19:37:34 +0300 | From | Maxim Levitsky <> | Subject | Re: [patch 2.6.26-rc5] make HPET_RTC_IRQ track HPET_EMULATE_RTC |
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David Brownell wrote: > On Friday 06 June 2008, Maxim Levitsky wrote: > >> Remember long ago I had a discussion with you about HPET that >> steals RTC irq in 'legacy replacement' mode, and rtc driver thus >> implements rtc on 'top' of hpet. >> >> New rtc-cmos driver doesn't do this emulation, thus it isn't compatible >> with hpet driver. > > That was fixed in 9d8af78b07976d4d84e0df491abd4e9db848d0ad (February) > by Bernhard Walle <bwalle@suse.de> ... if you look at the bug report > associated with this patch, you'll see that rtc-cmos was working OK > with HPET, it's just the legacy RTC driver which got confused after > the recent updates to clock handling. > > >> But there is a solution, I didn't agree with firstly, but then I did, and >> I do agree now, and that to put hpet in normal mode. >> >> What happened with patches that put hpet in normal independent mode? > > The story from either Ingo or Thomas (I forget who) was that this is > another case where we have to cope with BIOS braindamage. Not enough > BIOS vendors expose the relevant IRQ routing that Linux could default > to using HPET in what I'd call "sane" mode. > > Now, that still kind of implies there could be an option to use sane > HPET IRQ configuration (doesn't hijack RTC and other IRQs, and there > could be a per-CPU HPET) on at least the systems where that IRQ routing > is available. Over time I'd hope that systems like that could become > the common case. But ... someone else would have to do that work. :) > > - Dave
Thanks a lot, next time I compile the kernel, I will enable hpet
Best regards, Maxim Levitsky
PS:
This is a question to ubuntu devs, I need to ask them, when they will switch to new rtc driver....
Old driver has some bugs, including no support for suspend/resume, some troubles with alarm (it sets the alarm when writing to /proc/acpi/alarm, but it can be cleared by even just reading the time. New driver correctly sets the alarm at actual suspend time) Even hpet emulation has some bugs, I even wrote some patches to fix this and add suspend/resume, but I guess that newer driver is way better, so no need to fix old one.
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