* [PATCH] prepare speedstep-lib for 533 or 800 MHz FSB p4-m processors
@ 2003-11-04 19:36 Dominik Brodowski
0 siblings, 0 replies; only message in thread
From: Dominik Brodowski @ 2003-11-04 19:36 UTC (permalink / raw)
To: davej, cpufreq
[Note: this patch is probably too invasive for 2.6.0-testX.]
I don't know whether Intel has yet announced/produced/sold any Pentium 4-M
processors with 533 or 800 MHz FSB [quad-pumped 133 or 200 "real" MHz], but
let's get prepared for that eventuality in speedstep-lib :
diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c
--- linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c 2003-11-04 15:27:33.000000000 +0100
+++ linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c 2003-11-04 20:18:22.763662832 +0100
@@ -106,14 +106,45 @@
static unsigned int pentium4_get_frequency(void)
{
- u32 msr_lo, msr_hi;
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+ u32 msr_lo, msr_hi, mult;
+ unsigned int fsb = 0;
rdmsr(0x2c, msr_lo, msr_hi);
dprintk(KERN_DEBUG "speedstep-lib: P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi);
- msr_lo >>= 24;
- return (msr_lo * 100000);
+ /* decode the FSB: see IA-32 Intel (C) Architecture Software
+ * Developer's Manual, Volume 3: System Prgramming Guide,
+ * revision #12 in Table B-1: MSRs in the Pentium 4 and
+ * Intel Xeon Processors, on page B-4 and B-5.
+ */
+ if (c->x86_model < 2)
+ fsb = 100 * 1000;
+ else {
+ u8 fsb_code = (msr_lo >> 16) & 0x7;
+ switch (fsb_code) {
+ case 0:
+ fsb = 100 * 1000;
+ break;
+ case 1:
+ fsb = 13333 * 10;
+ break;
+ case 2:
+ fsb = 200 * 1000;
+ break;
+ }
+ }
+
+ if (!fsb)
+ printk(KERN_DEBUG "speedstep-lib: couldn't detect FSB speed. Please send an e-mail to <linux@brodo.de>\n");
+
+ /* Multiplier. */
+ mult = msr_lo >> 24;
+
+ dprintk(KERN_DEBUG "speedstep-lib: P4 - FSB %u kHz; Multiplier %u\n", fsb, mult);
+
+ return (fsb * mult);
}
diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h
--- linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h 2003-11-04 15:27:33.000000000 +0100
+++ linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h 2003-11-04 20:19:01.658749880 +0100
@@ -15,7 +15,7 @@
#define SPEEDSTEP_PROCESSOR_PIII_C_EARLY 0x00000001 /* Coppermine core */
#define SPEEDSTEP_PROCESSOR_PIII_C 0x00000002 /* Coppermine core */
#define SPEEDSTEP_PROCESSOR_PIII_T 0x00000003 /* Tualatin core */
-#define SPEEDSTEP_PROCESSOR_P4M 0x00000004 /* P4-M with 100 MHz FSB */
+#define SPEEDSTEP_PROCESSOR_P4M 0x00000004 /* P4-M */
/* speedstep states -- only two of them */
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2003-11-04 19:36 [PATCH] prepare speedstep-lib for 533 or 800 MHz FSB p4-m processors Dominik Brodowski
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