[tip:x86/platform] x86/platform/intel/baytrail: Add comments about why we disabled HPET on Baytrail
Commit-ID: b58d930750135d6c5b8e5aa084c0e9303c78c286 Gitweb: http://git.kernel.org/tip/b58d930750135d6c5b8e5aa084c0e9303c78c286 Author: Feng Tang AuthorDate: Mon, 15 Jun 2015 17:40:01 +0800 Committer: Ingo Molnar 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 Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner 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 --- 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/
[tip:x86/platform] x86/platform/intel/baytrail: Add comments about why we disabled HPET on Baytrail
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/