tools / power: turbostat: Drop temperature checks

The Intel 64 and IA-32 Architectures Software Developer's Manual says
that TjMax is stored in bits 23:16 of MSR_TEMPERATURE TARGET (0x1a2).
That's 8 bits, not 7, so it must be masked with 0xFF rather than 0x7F.

The manual has no mention of which values should be considered valid,
which kind of implies that they all are. Arbitrarily discarding values
outside a specific range is wrong. The upper range check had to be
fixed recently (commit 144b44b1) and the lower range check is just as
wrong. See bug #75071:

https://bugzilla.kernel.org/show_bug.cgi?id=75071

There are many Xeon processor series with TjMax of 70, 71 or 80
degrees Celsius, way below the arbitrary 85 degrees Celsius limit.
There may be other (past or future) models with even lower limits.

So drop this arbitrary check. The only value that would be clearly
invalid is 0. Everything else should be accepted.

After these changes, turbostat is aligned with what the coretemp
driver does.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Len Brown <len.brown@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 7c9d8e71eb9e..d0396af99fa0 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -1971,13 +1971,13 @@ int set_temperature_target(struct thread_data *t, struct core_data *c, struct pk
 	if (get_msr(0, MSR_IA32_TEMPERATURE_TARGET, &msr))
 		goto guess;
 
-	target_c_local = (msr >> 16) & 0x7F;
+	target_c_local = (msr >> 16) & 0xFF;
 
 	if (verbose)
 		fprintf(stderr, "cpu%d: MSR_IA32_TEMPERATURE_TARGET: 0x%08llx (%d C)\n",
 			cpu, msr, target_c_local);
 
-	if (target_c_local < 85 || target_c_local > 127)
+	if (!target_c_local)
 		goto guess;
 
 	tcc_activation_temp = target_c_local;