在 2018/5/24 15:45, Rafael J. Wysocki 写道:
On Thu, May 24, 2018 at 8:43 AM, Kevin Wangtao
<kevin.wang...@hisilicon.com> wrote:
consider such situation, current user_policy.min is 1000000,
current user_policy.max is 1200000, in cpufreq_set_policy,
other driver may update policy.min to 1200000, policy.max to
1300000. After that, If we input "echo 1300000 > scaling_min_freq",
then user_policy.min will be 1300000, and user_policy.max is
still 1200000, because the input value is checked with policy.max
not user_policy.max. if we get all related cpus offline and
online again, it will cause cpufreq_init_policy fail because
user_policy.min is higher than user_policy.max.
How do you reproduce this, exactly?
I can also reproduce this issue with upstream code, write max frequency to
scaling_max_freq
and scaling_min_freq, run benchmark to let cpu cooling take effect to clip
freq, then write
the cliped freq to scaling_max_freq, thus user_policy.min is still max
frequency but user_policy.max
is cliped freq which is lower than max frequency.
The solution is when user space tries to write scaling_(max|min)_freq,
the min/max of new_policy should be reinitialized with min/max
of user_policy, like what cpufreq_update_policy does.
Signed-off-by: Kevin Wangtao <kevin.wang...@hisilicon.com>
---
drivers/cpufreq/cpufreq.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index b79c532..8b33e08 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -697,6 +697,8 @@ static ssize_t store_##file_name
\
struct cpufreq_policy new_policy; \
\
memcpy(&new_policy, policy, sizeof(*policy)); \
+ new_policy->min = policy->user_policy.min; \
+ new_policy->max = policy->user_policy.max; \
It looks like you haven't even tried to build this, have you?
\
ret = sscanf(buf, "%u", &new_policy.object); \
if (ret != 1) \
--
2.8.1
.
