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Commit 46ef955f authored by Rafa Bilski's avatar Rafa Bilski Committed by Dave Jones
Browse files

[CPUFREQ] Longhaul - Fix guess_fsb function 



This is bug reported by John-Marc Chandonia:
> Detected 1002.292 MHz processor.
> longhaul: VIA C3 'Nehemiah B' [C5N] CPU detected.  Powersaver supported.
> longhaul: Using throttling support.
> longhaul: Invalid (reserved) FSB!
FSB is correcly guessed for 999.554 MHz CPU.
To fix this error:
- ROUNDING should be range, not mask - at it's current value it is +7 -8,
- more precise calculations inside guess_fsb - 7.5x133MHz is 1000MHz now.

Signed-off-by: default avatarRafal Bilski <rafalbilski@interia.pl>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 0d44b2ba

arch/i386/kernel/cpu/cpufreq/longhaul.c

+10 −22
Original line number Diff line number Diff line
@@ -318,31 +318,19 @@ static void longhaul_setstate(unsigned int clock_ratio_index) 


#define ROUNDING	0xf



static int _guess(int guess, int mult)

{

	int target;



	target = ((mult/10)*guess);

	if (mult%10 != 0)

		target += (guess/2);

	target += ROUNDING/2;

	target &= ~ROUNDING;

	return target;

}





static int guess_fsb(int mult)

{

	int speed = (cpu_khz/1000);

	int speed = cpu_khz / 1000;

	int i;

	int speeds[] = { 66, 100, 133, 200 };



	speed += ROUNDING/2;

	speed &= ~ROUNDING;

	int speeds[] = { 666, 1000, 1333, 2000 };

	int f_max, f_min;



	for (i = 0; i < 4; i++) {

		if (_guess(speeds[i], mult) == speed)

			return speeds[i];

		f_max = ((speeds[i] * mult) + 50) / 100;

		f_max += (ROUNDING / 2);

		f_min = f_max - ROUNDING;

		if ((speed <= f_max) && (speed >= f_min))

			return speeds[i] / 10;

	}

	return 0;

}