2016-03-18 21:26:59

by Richard Cochran

Subject: [PATCH 5/5] cpufreq: acpi-cpufreq: Clean up hot plug notifier callback.

This driver has two issues. First, it tries to fiddle with the hot
plugged CPU's MSR on the UP_PREPARE event, at a time when the CPU is
not yet online. Second, the driver sets the "boost-disable" bit for a
CPU when going down, but does not clear the bit again if the CPU comes
up again due to DOWN_FAILED.

This patch fixes the issues by changing the driver to react to the
ONLINE/DOWN_FAILED events instead of UP_PREPARE. As an added benefit,
the driver also becomes symmetric with respect to the hot plug
mechanism.

Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: [email protected]
Signed-off-by: Richard Cochran <[email protected]>
---
drivers/cpufreq/acpi-cpufreq.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 51eef87..7006a43 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -540,8 +540,10 @@ static int boost_notify(struct notifier_block *nb, unsigned long action,
*/

switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
+ case CPU_DOWN_FAILED:
+ case CPU_DOWN_FAILED_FROZEN:
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
boost_set_msrs(acpi_cpufreq_driver.boost_enabled, cpumask);
break;

--
2.1.4

2016-03-23 21:24:35

by Rafael J. Wysocki

Subject: Re: [PATCH 5/5] cpufreq: acpi-cpufreq: Clean up hot plug notifier callback.

On Friday, March 18, 2016 10:26:11 PM Richard Cochran wrote:
> This driver has two issues. First, it tries to fiddle with the hot
> plugged CPU's MSR on the UP_PREPARE event, at a time when the CPU is
> not yet online. Second, the driver sets the "boost-disable" bit for a
> CPU when going down, but does not clear the bit again if the CPU comes
> up again due to DOWN_FAILED.
>
> This patch fixes the issues by changing the driver to react to the
> ONLINE/DOWN_FAILED events instead of UP_PREPARE. As an added benefit,
> the driver also becomes symmetric with respect to the hot plug
> mechanism.
>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Viresh Kumar <[email protected]>
> Cc: [email protected]
> Signed-off-by: Richard Cochran <[email protected]>
> ---
> drivers/cpufreq/acpi-cpufreq.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 51eef87..7006a43 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -540,8 +540,10 @@ static int boost_notify(struct notifier_block *nb, unsigned long action,
> */
>
> switch (action) {
> - case CPU_UP_PREPARE:
> - case CPU_UP_PREPARE_FROZEN:
> + case CPU_DOWN_FAILED:
> + case CPU_DOWN_FAILED_FROZEN:
> + case CPU_ONLINE:
> + case CPU_ONLINE_FROZEN:
> boost_set_msrs(acpi_cpufreq_driver.boost_enabled, cpumask);
> break;

Applied, thanks!