linux-kernel - [PATCH 03/10] x86 tsc_msr: Remove debugging messages

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Message-Id: <cf03279a125b95dfa9b8d3d5b4a66de09cd04050.1466138954.git.len.brown@intel.com>
Date:	Fri, 17 Jun 2016 01:22:45 -0400
From:	Len Brown <lenb@...nel.org>
To:	x86@...nel.org
Cc:	linux-kernel@...r.kernel.org, Len Brown <len.brown@...el.com>
Subject: [PATCH 03/10] x86 tsc_msr: Remove debugging messages

From: Len Brown <len.brown@...el.com>

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: Len Brown <len.brown@...el.com>
---
 arch/x86/kernel/tsc_msr.c | 19 +++----------------
 1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c
index 4ec5e56..f7ba44b 100644
--- a/arch/x86/kernel/tsc_msr.c
+++ b/arch/x86/kernel/tsc_msr.c
@@ -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;
 }
-- 
2.9.0