Commit-ID: b58d930750135d6c5b8e5aa084c0e9303c78c286 Gitweb: http://git.kernel.org/tip/b58d930750135d6c5b8e5aa084c0e9303c78c286 Author: Feng Tang <feng.t...@intel.com> AuthorDate: Mon, 15 Jun 2015 17:40:01 +0800 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 18 Jun 2015 10:57:38 +0200
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.t...@intel.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Andy Lutomirski <l...@amacapital.net> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Oleg Nesterov <o...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: john.stu...@linaro.org Cc: len.br...@intel.com Cc: matthew....@intel.com Link: http://lkml.kernel.org/r/1434361201-31743-1-git-send-email-feng.t...@intel.com [ Prettified things a bit. ] Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/early-quirks.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c index fe9f0b7..5cb9a4d 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}, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
