Thread (10 messages) 10 messages, 4 authors, 2021-05-13

Re: [PATCH v4] x86, sched: Fix the AMD CPPC maximum perf on some specific generations

From: Ingo Molnar <mingo@kernel.org>
Date: 2021-05-12 20:21:51
Also in: lkml, stable

* Huang Rui [off-list ref] wrote:
Some AMD Ryzen generations has different calculation method on maximum
perf. 255 is not for all asics, some specific generations should use 166
as the maximum perf. Otherwise, it will report incorrect frequency value
like below:

~ → lscpu | grep MHz
CPU MHz:                         3400.000
CPU max MHz:                     7228.3198
CPU min MHz:                     2200.0000
It would have been useful to also quote the 'after' part.
+u32 amd_get_highest_perf(void)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	if (c->x86 == 0x17 && ((c->x86_model >= 0x30 && c->x86_model < 0x40) ||
+			       (c->x86_model >= 0x70 && c->x86_model < 0x80)))
+	    return 166;
+
+	if (c->x86 == 0x19 && ((c->x86_model >= 0x20 && c->x86_model < 0x30) ||
+			       (c->x86_model >= 0x40 && c->x86_model < 0x70)))
+	    return 166;
I fixed these stray 4-space tabs.

Looks good otherwise - queued up in tip:sched/urgent.

Thanks,

	Ingo
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