[2.6.0 cpufreq] longhaul trouble

[2.6.0 cpufreq] longhaul trouble

[Jurgen Kramer]

When I insert the longhaul cpufreq module on my VIA EPIA 800 the system
completely freezes. It does not give any oops or other helpful error
message.

Through ACPI I can only use the throttling function, I can not switch
between 400 and 800 MHz.

Jurgen

output of /proc/cpu

processor       : 0
vendor_id       : CentaurHauls
cpu family      : 6
model           : 7
model name      : VIA Ezra
stepping        : 8
cpu MHz         : 800.048
cache size      : 64 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu de tsc msr cx8 mtrr pge mmx 3dnow
bogomips        : 1595.80

Re: [2.6.0 cpufreq] longhaul trouble

[Dave Jones]

On Fri, Dec 19, 2003 at 05:32:11PM +0100, Jurgen Kramer wrote:
 > When I insert the longhaul cpufreq module on my VIA EPIA 800 the system
 > completely freezes. It does not give any oops or other helpful error
 > message.
 > 

Does this help ?

	Dave

diff -urpN --exclude-from=/home/davej/.exclude bk-linus/arch/i386/kernel/cpu/cpufreq/longhaul.c cpufreq/arch/i386/kernel/cpu/cpufreq/longhaul.c
--- bk-linus/arch/i386/kernel/cpu/cpufreq/longhaul.c	2003-10-15 05:00:29.000000000 +0100
+++ cpufreq/arch/i386/kernel/cpu/cpufreq/longhaul.c	2003-11-21 02:20:59.000000000 +0000
@@ -170,6 +170,9 @@ static void longhaul_setstate (unsigned 
  * between that value multiplied by possible FSBs and cpu_mhz which
  * was calculated at boot time. Really ugly, but no other way to do this.
  */
+
+#define ROUNDING	0xf
+
 static int _guess (int guess, int maxmult)
 {
 	int target;
@@ -177,16 +180,20 @@ static int _guess (int guess, int maxmul
 	target = ((maxmult/10)*guess);
 	if (maxmult%10 != 0)
 		target += (guess/2);
-	target &= ~0xf;
+	target += ROUNDING/2;
+	target &= ~ROUNDING;
 	return target;
 }
 
 static int guess_fsb(int maxmult)
 {
-	int speed = (cpu_khz/1000) & ~0xf;
+	int speed = (cpu_khz/1000);
 	int i;
 	int speeds[3] = { 66, 100, 133 };
 
+	speed += ROUNDING/2;
+	speed &= ~ROUNDING;
+
 	for (i=0; i<3; i++) {
 		if (_guess(speeds[i],maxmult) == speed)
 			return speeds[i];

Re: [2.6.0 cpufreq] longhaul trouble

[Jurgen Kramer]

Yes it does!

from dmesg:

longhaul: VIA C3 'Ezra' [C5C] CPU detected. Longhaul v1 supported.
longhaul: MinMult=3.0x MaxMult=6.0x
longhaul: FSB: 133MHz Lowestspeed=399MHz Highestspeed=798MHz

from /sys/devices/system/cpu/cpu0/cpufreq:

::::::::::::::
cpuinfo_max_freq
::::::::::::::
798
::::::::::::::
cpuinfo_min_freq
::::::::::::::
399
::::::::::::::
scaling_available_governors
::::::::::::::
performance
::::::::::::::
scaling_driver
::::::::::::::
longhaul
::::::::::::::
scaling_governor
::::::::::::::
performance
::::::::::::::
scaling_max_freq
::::::::::::::
798
::::::::::::::
scaling_min_freq
::::::::::::::
399

Next step is to actually change the frequency. I am not really sure how
to do that with sysfs yet.

Cheers,

Jurgen