From 718be4aaf3613cf7c2d097f925abc3d3553c0605 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Thu, 22 Jul 2010 16:54:27 -0400 Subject: ACPI: skip checking BM_STS if the BIOS doesn't ask for it It turns out that there is a bit in the _CST for Intel FFH C3 that tells the OS if we should be checking BM_STS or not. Linux has been unconditionally checking BM_STS. If the chip-set is configured to enable BM_STS, it can retard or completely prevent entry into deep C-states -- as illustrated by turbostat: http://userweb.kernel.org/~lenb/acpi/utils/pmtools/turbostat/ ref: Intel Processor Vendor-Specific ACPI Interface Specification table 4 "_CST FFH GAS Field Encoding" Bit 1: Set to 1 if OSPM should use Bus Master avoidance for this C-state https://bugzilla.kernel.org/show_bug.cgi?id=15886 Signed-off-by: Len Brown --- arch/x86/kernel/acpi/cstate.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/x86/kernel/acpi') diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c index 2e837f5..fb7a5f0 100644 --- a/arch/x86/kernel/acpi/cstate.c +++ b/arch/x86/kernel/acpi/cstate.c @@ -145,6 +145,15 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, percpu_entry->states[cx->index].eax = cx->address; percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK; } + + /* + * For _CST FFH on Intel, if GAS.access_size bit 1 is cleared, + * then we should skip checking BM_STS for this C-state. + * ref: "Intel Processor Vendor-Specific ACPI Interface Specification" + */ + if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2)) + cx->bm_sts_skip = 1; + return retval; } EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe); -- cgit v1.1 From 72ad5d77fb981963edae15eee8196c80238f5ed0 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 23 Jul 2010 22:59:09 +0200 Subject: ACPI / Sleep: Allow the NVS saving to be skipped during suspend to RAM Commit 2a6b69765ad794389f2fc3e14a0afa1a995221c2 (ACPI: Store NVS state even when entering suspend to RAM) caused the ACPI suspend code save the NVS area during suspend and restore it during resume unconditionally, although it is known that some systems need to use acpi_sleep=s4_nonvs for hibernation to work. To allow the affected systems to avoid saving and restoring the NVS area during suspend to RAM and resume, introduce kernel command line option acpi_sleep=nonvs and make acpi_sleep=s4_nonvs work as its alias temporarily (add acpi_sleep=s4_nonvs to the feature removal file). Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16396 . Signed-off-by: Rafael J. Wysocki Reported-and-tested-by: tomas m Signed-off-by: Len Brown --- arch/x86/kernel/acpi/sleep.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/acpi') diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c index 82e5086..fcc3c61 100644 --- a/arch/x86/kernel/acpi/sleep.c +++ b/arch/x86/kernel/acpi/sleep.c @@ -157,9 +157,14 @@ static int __init acpi_sleep_setup(char *str) #ifdef CONFIG_HIBERNATION if (strncmp(str, "s4_nohwsig", 10) == 0) acpi_no_s4_hw_signature(); - if (strncmp(str, "s4_nonvs", 8) == 0) - acpi_s4_no_nvs(); + if (strncmp(str, "s4_nonvs", 8) == 0) { + pr_warning("ACPI: acpi_sleep=s4_nonvs is deprecated, " + "please use acpi_sleep=nonvs instead"); + acpi_nvs_nosave(); + } #endif + if (strncmp(str, "nonvs", 5) == 0) + acpi_nvs_nosave(); if (strncmp(str, "old_ordering", 12) == 0) acpi_old_suspend_ordering(); str = strchr(str, ','); -- cgit v1.1