[PATCH v2 1/2] intel_idle: re-work bxt_idle_state_table_update() and its helper

[PATCH v2 1/2] intel_idle: re-work bxt_idle_state_table_update() and its helper

[Jan Beulich]

Since irtl_ns_units[] has itself zero entries, make sure the caller
recognized those cases along with the MSR read returning zero, as zero
is not a valid value for exit_latency and target_residency.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
 drivers/idle/intel_idle.c |   29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

--- 4.7-rc5-intel-idle-BXT.orig/drivers/idle/intel_idle.c
+++ 4.7-rc5-intel-idle-BXT/drivers/idle/intel_idle.c
@@ -1154,6 +1154,9 @@ static unsigned long long irtl_2_usec(un
 {
 	unsigned long long ns;
 
+	if (!irtl)
+		return 0;
+
 	ns = irtl_ns_units[(irtl >> 10) & 0x3];
 
 	return div64_u64((irtl & 0x3FF) * ns, 1000);
@@ -1167,43 +1170,39 @@ static unsigned long long irtl_2_usec(un
 static void bxt_idle_state_table_update(void)
 {
 	unsigned long long msr;
+	unsigned int usec;
 
 	rdmsrl(MSR_PKGC6_IRTL, msr);
-	if (msr) {
-		unsigned int usec = irtl_2_usec(msr);
-
+	usec = irtl_2_usec(msr);
+	if (usec) {
 		bxt_cstates[2].exit_latency = usec;
 		bxt_cstates[2].target_residency = usec;
 	}
 
 	rdmsrl(MSR_PKGC7_IRTL, msr);
-	if (msr) {
-		unsigned int usec = irtl_2_usec(msr);
-
+	usec = irtl_2_usec(msr);
+	if (usec) {
 		bxt_cstates[3].exit_latency = usec;
 		bxt_cstates[3].target_residency = usec;
 	}
 
 	rdmsrl(MSR_PKGC8_IRTL, msr);
-	if (msr) {
-		unsigned int usec = irtl_2_usec(msr);
-
+	usec = irtl_2_usec(msr);
+	if (usec) {
 		bxt_cstates[4].exit_latency = usec;
 		bxt_cstates[4].target_residency = usec;
 	}
 
 	rdmsrl(MSR_PKGC9_IRTL, msr);
-	if (msr) {
-		unsigned int usec = irtl_2_usec(msr);
-
+	usec = irtl_2_usec(msr);
+	if (usec) {
 		bxt_cstates[5].exit_latency = usec;
 		bxt_cstates[5].target_residency = usec;
 	}
 
 	rdmsrl(MSR_PKGC10_IRTL, msr);
-	if (msr) {
-		unsigned int usec = irtl_2_usec(msr);
-
+	usec = irtl_2_usec(msr);
+	if (usec) {
 		bxt_cstates[6].exit_latency = usec;
 		bxt_cstates[6].target_residency = usec;
 	}

Re: [PATCH v2 1/2] intel_idle: re-work bxt_idle_state_table_update() and its helper

[Rafael J. Wysocki]

On Monday, June 27, 2016 12:35:12 AM Jan Beulich wrote:
> Since irtl_ns_units[] has itself zero entries, make sure the caller
> recognized those cases along with the MSR read returning zero, as zero
> is not a valid value for exit_latency and target_residency.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

This ans the [2/2] applied, thanks!