[PATCH v2 14/17] x86/acpi/cstate: Improve Intel Family model checks

Sohil Mehta posted 17 patches 12 months ago
There is a newer version of this series
[PATCH v2 14/17] x86/acpi/cstate: Improve Intel Family model checks
Posted by Sohil Mehta 12 months ago
Update the Intel Family checks to consistently use Family 15 instead of
Family 0xF. Also, get rid of one of last usages of x86_model by using
the new VFM checks.

Update the incorrect comment since the check has changed[1][2] since the
initial commit ee1ca48fae7e ("ACPI: Disable ARB_DISABLE on platforms
where it is not needed").

[1]: commit 3e2ada5867b7 ("ACPI: fix Compaq Evo N800c (Pentium 4m) boot
hang regression") removed the P4 - Family 15.

[2]: commit 03a05ed11529 ("ACPI: Use the ARB_DISABLE for the CPU which
model id is less than 0x0f.") got rid of CORE_YONAH - Family 6, model E.

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>

---

v2: Improve commit message.

---
 arch/x86/include/asm/intel-family.h | 3 +++
 arch/x86/kernel/acpi/cstate.c       | 8 ++++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h
index 300dac505d7f..fae52a15d9b9 100644
--- a/arch/x86/include/asm/intel-family.h
+++ b/arch/x86/include/asm/intel-family.h
@@ -187,6 +187,9 @@
 #define INTEL_XEON_PHI_KNL		IFM(6, 0x57) /* Knights Landing */
 #define INTEL_XEON_PHI_KNM		IFM(6, 0x85) /* Knights Mill */
 
+/* Notational marker denoting the last Family 6 model */
+#define INTEL_FAM6_LAST		        IFM(6, 0xFF)
+
 /* Family 15 - NetBurst */
 #define INTEL_P4_WILLAMETTE		IFM(15, 0x01) /* Also Xeon Foster */
 #define INTEL_P4_PRESCOTT		IFM(15, 0x03)
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index 5854f0b8f0f1..444602a0a3dd 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -13,6 +13,7 @@
 #include <linux/sched.h>
 
 #include <acpi/processor.h>
+#include <asm/cpu_device_id.h>
 #include <asm/cpuid.h>
 #include <asm/mwait.h>
 #include <asm/special_insns.h>
@@ -47,12 +48,11 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
 	/*
 	 * On all recent Intel platforms, ARB_DISABLE is a nop.
 	 * So, set bm_control to zero to indicate that ARB_DISABLE
-	 * is not required while entering C3 type state on
-	 * P4, Core and beyond CPUs
+	 * is not required while entering C3 type state.
 	 */
 	if (c->x86_vendor == X86_VENDOR_INTEL &&
-	    (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
-			flags->bm_control = 0;
+	    (c->x86 > 15 || (c->x86_vfm >= INTEL_CORE2_MEROM && c->x86_vfm <= INTEL_FAM6_LAST)))
+		flags->bm_control = 0;
 
 	if (c->x86_vendor == X86_VENDOR_CENTAUR) {
 		if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f &&
-- 
2.43.0
Re: [PATCH v2 14/17] x86/acpi/cstate: Improve Intel Family model checks
Posted by Dave Hansen 12 months ago
On 2/11/25 11:44, Sohil Mehta wrote:
> Update the Intel Family checks to consistently use Family 15 instead of
> Family 0xF. Also, get rid of one of last usages of x86_model by using
> the new VFM checks.
> 
> Update the incorrect comment since the check has changed[1][2] since the
> initial commit ee1ca48fae7e ("ACPI: Disable ARB_DISABLE on platforms
> where it is not needed").
> 
> [1]: commit 3e2ada5867b7 ("ACPI: fix Compaq Evo N800c (Pentium 4m) boot
> hang regression") removed the P4 - Family 15.
> 
> [2]: commit 03a05ed11529 ("ACPI: Use the ARB_DISABLE for the CPU which
> model id is less than 0x0f.") got rid of CORE_YONAH - Family 6, model E.
> 
> Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>