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| author | Feng Tang <feng.tang@intel.com> | 2015-06-15 11:40:01 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-06-18 10:57:38 +0200 |
| commit | b58d930750135d6c5b8e5aa084c0e9303c78c286 (patch) | |
| tree | fd7aacf41b5fbc6e6d3c7ffae910aa2322450a9c /arch | |
| parent | x86/platform/atom/punit: Add Punit device state debug driver (diff) | |
| download | linux-b58d930750135d6c5b8e5aa084c0e9303c78c286.tar.xz linux-b58d930750135d6c5b8e5aa084c0e9303c78c286.zip | |
x86/platform/intel/baytrail: Add comments about why we disabled HPET on Baytrail
This question has been asked many times, and finally I found the
official document which explains the problem of HPET on Baytrail,
that it will halt in deep idle states.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john.stultz@linaro.org
Cc: len.brown@intel.com
Cc: matthew.lee@intel.com
Link: http://lkml.kernel.org/r/1434361201-31743-1-git-send-email-feng.tang@intel.com
[ Prettified things a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/early-quirks.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c index fe9f0b79a18b..5cb9a4d6f623 100644 --- a/arch/x86/kernel/early-quirks.c +++ b/arch/x86/kernel/early-quirks.c @@ -627,8 +627,12 @@ static struct chipset early_qrk[] __initdata = { { PCI_VENDOR_ID_INTEL, PCI_ANY_ID, PCI_CLASS_DISPLAY_VGA, PCI_ANY_ID, QFLAG_APPLY_ONCE, intel_graphics_stolen }, /* - * HPET on current version of Baytrail platform has accuracy - * problems, disable it for now: + * HPET on the current version of the Baytrail platform has accuracy + * problems: it will halt in deep idle state - so we disable it. + * + * More details can be found in section 18.10.1.3 of the datasheet: + * + * http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/atom-z8000-datasheet-vol-1.pdf */ { PCI_VENDOR_ID_INTEL, 0x0f00, PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet}, |