[PATCH] Add additional Intel CPU models to crystal_khz whitelist

[PATCH] Add additional Intel CPU models to crystal_khz whitelist

[Prarit Bhargava]

In commit aa297292d708 ("x86/tsc: Enumerate SKL cpu_khz and tsc_khz via
CPUID"), the kernel added support for Intel processors which had
a different CPU base-frequency and TSC frequency.

The turbostat utility has been updated with KBL and SKX processors,
and they should also be added to the crystal_khz white list.

For example, on KBL (0x8E) native_calibrate_tsc() returns 0 MHz for
tsc_khz and after this patch native_calibrate_tsc() returns 1608 MHz.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Rafael Aquini <aquini@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: lenb@kernel.org
---
 arch/x86/kernel/tsc.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 78b9cb5a26af..421ddbbf3fc8 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -688,11 +688,19 @@ unsigned long native_calibrate_tsc(void)
 		switch (boot_cpu_data.x86_model) {
 		case 0x4E:	/* SKL */
 		case 0x5E:	/* SKL */
+		case 0x8E:	/* KBL */
+		case 0x9E:	/* KBL */
 			crystal_khz = 24000;	/* 24.0 MHz */
 			break;
+		case 0x55:	/* SKX */
+			crystal_khz = 25000;	/* 25.0 MHz */
+			break;
 		case 0x5C:	/* BXT */
 			crystal_khz = 19200;	/* 19.2 MHz */
 			break;
+		default:
+			crystal_khz = 0;
+
 		}
 	}
 
-- 
1.7.9.3

Re: [PATCH] Add additional Intel CPU models to crystal_khz whitelist

[Thomas Gleixner]

On Fri, 9 Sep 2016, Prarit Bhargava wrote:

> In commit aa297292d708 ("x86/tsc: Enumerate SKL cpu_khz and tsc_khz via

You cite a commit here, which is nice. If you look at the commit message
then you will notice that _before_ the sentence describing the commit there
is a prefix, which denotes the subsystem to which this patch applies. But
you insist on sending patches w/o a prefix.

Can you please stop this? It's annoying because I have to figure out where
the patch belongs to and have to edit the subject line before applying the
patch.


> @@ -688,11 +688,19 @@ unsigned long native_calibrate_tsc(void)
>  		switch (boot_cpu_data.x86_model) {
>  		case 0x4E:	/* SKL */
>  		case 0x5E:	/* SKL */
> +		case 0x8E:	/* KBL */
> +		case 0x9E:	/* KBL */

asm/intel-family.h provides proper defines for this. And before you add
those, please make a seperate patch which converts the existing hex
constants to the defines.

Thanks,

	tglx