[SRU,Artful,3/3] x86/tsc: Print tsc_khz, when it differs from cpu_khz

Message ID 69782a41f813f1fca8b24e9d2f15efb20aeed510.1517423725.git.joseph.salisbury@canonical.com
State New
Headers show
Series
  • Untitled series #26525
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Commit Message

Joseph Salisbury Feb. 1, 2018, 6:59 p.m.
From: Len Brown <len.brown@intel.com>

BugLink: http://bugs.launchpad.net/bugs/1744988

If CPU and TSC frequency are the same the printout of the CPU frequency is
valid for the TSC as well:

      tsc: Detected 2900.000 MHz processor

If the TSC frequency is different there is no information in dmesg. Add a
conditional printout:

  tsc: Detected 2904.000 MHz TSC

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: peterz@infradead.org
Link: https://lkml.kernel.org/r/537b342debcd8e8aebc8d631015dcdf9f9ba8a26.1513920414.git.len.brown@intel.com

(cherry picked from commit 4b5b2127238e689ee18aa6752959751dd61c4c73)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
---
 arch/x86/kernel/tsc.c | 6 ++++++
 1 file changed, 6 insertions(+)

Patch

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 0be7a5f..0fc353b 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1297,6 +1297,12 @@  void __init tsc_init(void)
 		(unsigned long)cpu_khz / 1000,
 		(unsigned long)cpu_khz % 1000);
 
+	if (cpu_khz != tsc_khz) {
+		pr_info("Detected %lu.%03lu MHz TSC",
+			(unsigned long)tsc_khz / 1000,
+			(unsigned long)tsc_khz % 1000);
+	}
+
 	/* Sanitize TSC ADJUST before cyc2ns gets initialized */
 	tsc_store_and_check_tsc_adjust(true);