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Commit 3581ced3 authored by Borislav Petkov's avatar Borislav Petkov Committed by Dave Jones
Browse files

[CPUFREQ] powernow-k8: Limit Pstate transition latency check 



The Pstate transition latency check was added for broken F10h BIOSen
which wrongly contain a value of 0 for transition and bus master
latency. Fam11h and later, however, (will) have similar transition
latency so extend that behavior for them too.

Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 179ee434

arch/x86/kernel/cpu/cpufreq/powernow-k8.c

+5 −6
Original line number Diff line number Diff line
@@ -1023,13 +1023,12 @@ static int get_transition_latency(struct powernow_k8_data *data) 
	}

	if (max_latency == 0) {

		/*

		 * Fam 11h always returns 0 as transition latency.

		 * This is intended and means "very fast". While cpufreq core

		 * and governors currently can handle that gracefully, better

		 * set it to 1 to avoid problems in the future.

		 * For all others it's a BIOS bug.

		 * Fam 11h and later may return 0 as transition latency. This

		 * is intended and means "very fast". While cpufreq core and

		 * governors currently can handle that gracefully, better set it

		 * to 1 to avoid problems in the future.

		 */

		if (boot_cpu_data.x86 != 0x11)

		if (boot_cpu_data.x86 < 0x11)

			printk(KERN_ERR FW_WARN PFX "Invalid zero transition "

				"latency\n");

		max_latency = 1;