On 2015-12-15 22:02, Prarit Bhargava wrote:
> The MSR_PKG_POWER_INFO register (Intel ASDM, section 14.9.3
> "Package RAPL Domain") provides a maximum time window which the
> system can support. This window is read-only and is currently
> not examined when setting the time windows for the package.
I have been having a question here long time.
Maximum Time Window (bits 53:48) in MSR_PKG_POWER_INFO is only
6-bit length even though Time Window for Power Limit #1 (bits 23:17)
and Time Window for Power Limit #2 (bits 55:49) in MSR_PKG_POWER_LIMIT
are both 7-bit length, not 6.
Do Intel guys have an answer for it?
The patch itself looks good to me.
Just minor comments below:
> diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
> index cc97f08..f765b2c 100644
> --- a/drivers/powercap/intel_rapl.c
> +++ b/drivers/powercap/intel_rapl.c
> @@ -493,13 +493,42 @@ static int get_current_power_limit(struct powercap_zone
> *power_zone, int id,
> return ret;
> }
>
> +static int get_max_time_window(struct powercap_zone *power_zone, int id,
The 2nd arg "id" is not necessary.
> + u64 *data)
> +{
> + struct rapl_domain *rd;
> + int ret = 0;
> + u64 val;
> +
> + get_online_cpus();
> + rd = power_zone_to_rapl_domain(power_zone);
> +
> + if (rapl_read_data_raw(rd, MAX_TIME_WINDOW, true, &val))
rapl_read_data_raw() can return -EINVAL and -ENODEV other than -EIO.
> + ret = -EIO;
Is it OK to limit ret to -EIO here?
> + else
> + *data = val;
> +
> + put_online_cpus();
> + return ret;
> +}
> +
> static int set_time_window(struct powercap_zone *power_zone, int id,
> u64 window)
> {
> struct rapl_domain *rd;
> int ret = 0;
> + u64 max_window;
>
> get_online_cpus();
> + ret = get_max_time_window(power_zone, id, &max_window);
> + if (ret < 0)
> + goto out;
> +
> + if (window > max_window) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> rd = power_zone_to_rapl_domain(power_zone);
> switch (rd->rpl[id].prim_id) {
> case PL1_ENABLE:
> @@ -511,6 +540,7 @@ static int set_time_window(struct powercap_zone
> *power_zone, int id,
> default:
> ret = -EINVAL;
> }
> +out:
> put_online_cpus();
> return ret;
> }
> @@ -590,6 +620,7 @@ static struct powercap_zone_constraint_ops constraint_ops
> = {
> .set_time_window_us = set_time_window,
> .get_time_window_us = get_time_window,
> .get_max_power_uw = get_max_power,
> + .get_max_time_window_us = get_max_time_window,
> .get_name = get_constraint_name,
> };
>
> diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c
> index 84419af..7d77b83 100644
> --- a/drivers/powercap/powercap_sys.c
> +++ b/drivers/powercap/powercap_sys.c
> @@ -101,7 +101,7 @@ static ssize_t store_constraint_##_attr(struct device
> *dev,\
> int err; \
> u64 value; \
> struct powercap_zone *power_zone = to_powercap_zone(dev); \
> - int id; \
> + int id, ret; \
> struct powercap_zone_constraint *pconst;\
> \
> if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
> @@ -113,8 +113,10 @@ static ssize_t store_constraint_##_attr(struct device
> *dev,\
> if (err) \
> return -EINVAL; \
> if (pconst && pconst->ops && pconst->ops->set_##_attr) { \
> - if (!pconst->ops->set_##_attr(power_zone, id, value)) \
> + ret = pconst->ops->set_##_attr(power_zone, id, value); \
> + if (!ret) \
> return count; \
> + return ret; \
An opposite question to above.
Is it OK not to limit the return value to -EINVAL here?
Do you want this function to return -EIO or something?
> } \
> \
> return -ENODATA; \
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
