Re: [Patch 1/6] cpufreq: use correct unit when verify cur freq

From: Sumit Gupta
Date: Tue Apr 18 2023 - 09:32:16 EST




On 18/04/23 18:27, Rafael J. Wysocki wrote:
External email: Use caution opening links or attachments


On Tue, Apr 18, 2023 at 1:35 PM Sumit Gupta <sumitg@xxxxxxxxxx> wrote:

From: Sanjay Chandrashekara <sanjayc@xxxxxxxxxx>

cpufreq_verify_current_freq checks if the frequency returned by
the hardware has a slight delta with the valid frequency value
last set and returns "policy->cur" if the delta is within "1 MHz".
In the comparison, "policy->cur" is in "kHz" but it's compared
against HZ_PER_MHZ. So, the comparison range becomes "1 GHz".
Fix this by comparing against KHZ_PER_MHZ instead of HZ_PER_MHZ.

Fixes: f55ae08c8987 ("cpufreq: Avoid unnecessary frequency updates due to mismatch")
Signed-off-by: Sanjay Chandrashekara <sanjayc@xxxxxxxxxx>
[ sumit gupta: Commit message update ]
Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 8b0509f89f1b..6b52ebe5a890 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1732,7 +1732,7 @@ static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, b
* MHz. In such cases it is better to avoid getting into
* unnecessary frequency updates.
*/
- if (abs(policy->cur - new_freq) < HZ_PER_MHZ)
+ if (abs(policy->cur - new_freq) < KHZ_PER_MHZ)
return policy->cur;

cpufreq_out_of_sync(policy, new_freq);
--

So this is a fix that can be applied separately from the rest of the
series, isn't it?

Yes.

Thank you,
Sumit Gupta