[patch 0/4] Only use HPET MSI timers on systems with deep C-state support
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From: Venkatesh Pallipadi on 14 Jan 2010 21:00 There is a functionality issue reported on some AMD platforms http://lkml.indiana.edu/hypermail/linux/kernel/0912.2/01118.html wherein, fdformat fails when HPET MSI based percpu timer is used. We do not have the real root-cause for that problem. But, that report exposed an issue with our current usage HPET MSI timers. We use HPET MSI timers even on platforms that do not have support for C2/C3 states. On those systems we should rather be using LAPIC timers. So, this series of patches does just that. * Use LAPIC timer when there is always running APIC timer * Use LAPIC timer on platforms that do not have support for deep C states * Only use HPET MSI timers as percpu timers on systems that have LAPICs that stop in deep C-states _and_ system supports deep C-states The change turned out to be more than what I expected, due to the current static nature of clockevent rating and unrelated issues in acpi processor driver resume path. I also ended up touching different subsystems to handle this. If the patchset resolves the issue for Mark and if it looks sane can one of the maintainers queue it up for .34 Reported-by: Mark Hounschell <markh(a)compro.net> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi(a)intel.com> -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |