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Commit 14bb4e34 authored by Len Brown's avatar Len Brown Committed by Ingo Molnar
Browse files

x86/tsc_msr: Remove debugging messages 



Debugging messages are not necessary after all of the
possible hardware failures that never occur.
Instead, this code can simply return 0.

This code also doesn't need to print in the success case.
tsc_init() already prints the TSC frequency,
and apic=debug is available if anybody really is
interested in printing the LAPIC frequency.

Signed-off-by: default avatarLen Brown <len.brown@intel.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/cf03279a125b95dfa9b8d3d5b4a66de09cd04050.1466138954.git.len.brown@intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ba826833

arch/x86/kernel/tsc_msr.c

+3 −16
Original line number Diff line number Diff line
@@ -76,9 +76,10 @@ static int match_cpu(u8 family, u8 model) 
	(freq_desc_tables[cpu_index].freqs[freq_id])



/*

 * Do MSR calibration only for known/supported CPUs.

 * MSR-based CPU/TSC frequency discovery for certain CPUs.

 *

 * Returns the calibration value or 0 if MSR calibration failed.

 * Set global "lapic_timer_frequency" to bus_clock_cycles/jiffy

 * Return processor base frequency in KHz, or 0 on failure.

 */

unsigned long try_msr_calibrate_tsc(void)

{
@@ -100,31 +101,17 @@ unsigned long try_msr_calibrate_tsc(void) 
		rdmsr(MSR_IA32_PERF_STATUS, lo, hi);

		ratio = (hi >> 8) & 0x1f;

	}

	pr_info("Maximum core-clock to bus-clock ratio: 0x%x\n", ratio);



	if (!ratio)

		goto fail;



	/* Get FSB FREQ ID */

	rdmsr(MSR_FSB_FREQ, lo, hi);

	freq_id = lo & 0x7;

	freq = id_to_freq(cpu_index, freq_id);

	pr_info("Resolved frequency ID: %u, frequency: %u KHz\n",

				freq_id, freq);

	if (!freq)

		goto fail;



	/* TSC frequency = maximum resolved freq * maximum resolved bus ratio */

	res = freq * ratio;

	pr_info("TSC runs at %lu KHz\n", res);



#ifdef CONFIG_X86_LOCAL_APIC

	lapic_timer_frequency = (freq * 1000) / HZ;

	pr_info("lapic_timer_frequency = %d\n", lapic_timer_frequency);

#endif

	return res;



fail:

	pr_warn("Fast TSC calibration using MSR failed\n");

	return 0;

}