Re: [PATCH] x86/ACPI/cstate: Output AMD on APCI C1 FFH MWAIT AMD systems

From: Pavel Machek
Date: Wed Aug 08 2018 - 15:59:01 EST


On Wed 2018-08-08 13:47:35, Prarit Bhargava wrote:
> commit 5209654a46ee ("x86/ACPI/cstate: Allow ACPI C1 FFH MWAIT use on AMD
> systems") allows use of FFH for ACPI C1 but tools like cpupower and turbostat
> display INTEL for the cstate description.
>
> Output "AMD" for AMD systems with FFH for ACPI C1.

Um, is it good idea?

First, you are changing kernel API.

> @@ -107,9 +108,14 @@ static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
> "Monitor-Mwait will be used to enter C-%d state\n",
> cx->type);
> }
> - snprintf(cx->desc,
> - ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
> - cx->address);
> + if (c->x86_vendor == X86_VENDOR_INTEL)
> + snprintf(cx->desc,
> + ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
> + cx->address);
> + else
> + snprintf(cx->desc,
> + ACPI_CX_DESC_LEN, "ACPI FFH AMD MWAIT 0x%x",
> + cx->address);

Second, I read it as "Intel MWAIT" instruction is used. Yes, AMD cpu can
use Intel MWAIT, too...

Third, there are more CPU vendors out there.

Pavel
--
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