Re: [acpi-jp 2870] ACPI throttling changes

From: Taku YAMAMOTO <taku_at_cent.saitama-u.ac.jp>
Date: Fri, 12 Dec 2003 16:59:54 +0900
On Thu, 11 Dec 2003 23:07:42 -0600
Ryan Sommers <ryans_at_gamersimpact.com> wrote:
> Here are my results from testing this patch. It appears as though the
> stepping "works" for the first step and not again. However, the first
> step shows a approx. 20% increase, I was expecting something closer to
> 12.5%.

I think we need (CPU_MAX_SPEED-1) instead of CPU_MAX_SPEED when calculating
mask value (in acpi_cpu_throttle_set()):

--- src/sys/dev/acpica/acpi_cpu.c.orig	Fri Nov 28 01:32:46 2003
+++ src/sys/dev/acpica/acpi_cpu.c	Sat Nov 29 20:41:28 2003
_at__at_ -780,7 +780,7 _at__at_
 	/* If we're at maximum speed, that's all */
 	if (speed < CPU_MAX_SPEED) {
 	    /* Mask the old CLK_VAL off and or-in the new value */
-	    clk_val = CPU_MAX_SPEED << cpu_duty_offset;
+	    clk_val = (CPU_MAX_SPEED - 1) << cpu_duty_offset;
 	    p_cnt &= ~clk_val;
 	    p_cnt |= (speed << cpu_duty_offset);
 	

regards,
Taku
-- 
-|-__    YAMAMOTO, Taku  <taku_at_cent.saitama-u.ac.jp>
 | __ <
Received on Thu Dec 11 2003 - 23:00:06 UTC

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