On Friday 26 October 2007 01:43, Zhao Yakui wrote: > Hi, all > According to the document of 253369(intel), the ratio is > undefined in MSR_FBC_REGSITER_ID. The following calculation is > inappropriate. > if (c->x86_model < 2) > mult = msr_lo >> 27; > > There are two ways to fix this problem. > a. use the following patch. the ratio is obtained from model string. > b. revert the commit until the proper patch is available. > > http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commit;h=3e4159ab35c88aef5e063ba78796b277b762a30a Okay, I've reverted that patch -- so model 0&1 are back to where they were in 2005 and random MHz is replaced by other random MHz. > > Subject: ACPI :Obtain FSB ratio from model string when model is less than 2 > >From : Zhao Yakui <yakui.zhao@xxxxxxxxx> > > The ratio is undefined in the register of MSR_FBC_REGSITER_ID > when the model for P4 is less than 2. The following calculation is > inappropriate. > if (c->x86_model < 2) > mult = msr_lo >> 27; > In order to support the speedstep , the FSb ratio can be obtained from > the model_id string. > For example: > The ratio is 13 for model string:"Intel(R) Pentium(R) 4 CPU 1300MHz" > > http://bugzilla.kernel.org/show_bug.cgi?id=7186 > > Signed-off-by: Zhao Yakui <yakui.zhao@xxxxxxxxx> > --- > arch/i386/kernel/cpu/cpufreq/speedstep-lib.c | 40 +++++++++++++++++++++++++-- > 1 file changed, 38 insertions(+), 2 deletions(-) > > Index: linux-2.6.23-rc9/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c > =================================================================== > --- linux-2.6.23-rc9.orig/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c > +++ linux-2.6.23-rc9/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c > @@ -17,6 +17,7 @@ > > #include <asm/msr.h> > #include "speedstep-lib.h" > +#include <linux/ctype.h> > > #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-lib", msg) > > @@ -151,7 +152,40 @@ static unsigned int pentium_core_get_fre > > return (msr_tmp * fsb); > } > - > +/* When Model_id is less than 2, the FSB ratio is > +obtained from the string of model_id */ > +static unsigned int p4_01_get_fsb_ratio(void) > +{ > + struct cpuinfo_x86 *c = &boot_cpu_data; > + unsigned int fsb_m; > + char model_id[64]; > + unsigned int freq_mhz; > + unsigned int max_ratio; > + char *ptr; > + int i = 0; > + > + ptr = model_id; > + strncpy(ptr, c->x86_model_id, strlen(c->x86_model_id)); > + for (i = 0; i < strlen(model_id); i++) > + model_id[i] = tolower(model_id[i]); > + if (strstr(model_id, "mhz")) > + fsb_m = 100; > + else > + fsb_m = 0; > + if (!fsb_m) { > + printk(KERN_DEBUG "CPU doesn't support speedstep\n"); > + return 0; > + } > + ptr = strstr(model_id, "hz"); > + if (ptr) > + *ptr = '\0'; > + freq_mhz = 0; > + ptr = strrchr(model_id, ' '); > + if (ptr) > + sscanf(ptr, "%d", &freq_mhz); > + max_ratio = freq_mhz / fsb_m; > + return max_ratio; > +} > > static unsigned int pentium4_get_frequency(void) > { > @@ -189,8 +223,10 @@ static unsigned int pentium4_get_frequen > printk(KERN_DEBUG "speedstep-lib: couldn't detect FSB speed. Please send an e-mail to <linux@xxxxxxxx>\n"); > > /* Multiplier. */ > + /* if Model is less than 2 , the ratio is obtained from the > + * string of model_id */ > if (c->x86_model < 2) > - mult = msr_lo >> 27; > + mult = p4_01_get_fsb_ratio(); > else > mult = msr_lo >> 24; > I'm not excited about adding code to parse the model string, particularly when the justification is an early P4 model that doesn't even support P-states. I'd prefer to see p4-clockmod deleted from the kernel. -Len - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
