[Midnightbsd-cvs] src [6577] trunk/sys/x86/cpufreq/est.c: do not delay for P-state transition unless we want the result.

[laffer1 at midnightbsd.org]

Revision: 6577
          http://svnweb.midnightbsd.org/src/?rev=6577
Author:   laffer1
Date:     2013-12-29 15:44:13 -0500 (Sun, 29 Dec 2013)
Log Message:
-----------
do not delay for P-state transition unless we want the result.

Modified Paths:
--------------
    trunk/sys/x86/cpufreq/est.c

Modified: trunk/sys/x86/cpufreq/est.c
===================================================================
--- trunk/sys/x86/cpufreq/est.c	2013-12-29 20:41:54 UTC (rev 6576)
+++ trunk/sys/x86/cpufreq/est.c	2013-12-29 20:44:13 UTC (rev 6577)
@@ -1288,10 +1288,9 @@
 	msr = (msr & ~0xffff) | id16;
 	wrmsr(MSR_PERF_CTL, msr);
 
-	/* Wait a short while for the new setting.  XXX Is this necessary? */
-	DELAY(EST_TRANS_LAT);
-
 	if  (need_check) {
+		/* Wait a short while and read the new status. */
+		DELAY(EST_TRANS_LAT);
 		est_get_id16(&new_id16);
 		if (new_id16 != id16) {
 			if (bootverbose)