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authorVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>2017-08-23 20:58:41 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2017-11-12 22:00:29 +0100
commit8d4e10e9ed9450e18fbbf6a8872be0eac9fd4999 (patch)
treeb253e20bfac899bb3b9bfec1ab62e473f7978fdc
parentpowerpc/kprobes: refactor kprobe_lookup_name for safer string operations (diff)
downloadlinux-8d4e10e9ed9450e18fbbf6a8872be0eac9fd4999.tar.xz
linux-8d4e10e9ed9450e18fbbf6a8872be0eac9fd4999.zip
powerpc/powernv/idle: Round up latency and residency values
On PowerNV platforms, firmware provides exit latency and target residency for each of the idle states in nano seconds. Cpuidle framework expects the values in micro seconds. Round up to nearest micro seconds to avoid errors in cases where the values are defined as fractional micro seconds. Default idle state of 'snooze' has exit latency of zero. If other states have fractional micro second exit latency, they would get rounded down to zero micro second and make cpuidle framework choose deeper idle state when snooze loop is the right choice. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--drivers/cpuidle/cpuidle-powernv.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 42896a67aeae..5f3922392059 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -383,9 +383,9 @@ static int powernv_add_idle_states(void)
* Firmware passes residency and latency values in ns.
* cpuidle expects it in us.
*/
- exit_latency = latency_ns[i] / 1000;
+ exit_latency = DIV_ROUND_UP(latency_ns[i], 1000);
if (!rc)
- target_residency = residency_ns[i] / 1000;
+ target_residency = DIV_ROUND_UP(residency_ns[i], 1000);
else
target_residency = 0;