linux-kernel - Re: [PATCH 1/3] soc: qcom: rpmh: Update dirty flag only when data changes

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Date:   Wed, 5 Feb 2020 09:44:41 +0530
From:   Maulik Shah <mkshah@...eaurora.org>
To:     Evan Green <evgreen@...omium.org>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Lina Iyer <ilina@...eaurora.org>, lsrao@...eaurora.org
Subject: Re: [PATCH 1/3] soc: qcom: rpmh: Update dirty flag only when data
 changes


On 2/5/2020 6:05 AM, Evan Green wrote:
> On Mon, Feb 3, 2020 at 10:14 PM Maulik Shah <mkshah@...eaurora.org> wrote:
>> Currently rpmh ctrlr dirty flag is set for all cases regardless
>> of data is really changed or not.
>>
>> Add changes to update it when data is updated to new values.
>>
>> Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
>> ---
>>   drivers/soc/qcom/rpmh.c | 15 +++++++++++----
>>   1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
>> index 035091f..c3d6f00 100644
>> --- a/drivers/soc/qcom/rpmh.c
>> +++ b/drivers/soc/qcom/rpmh.c
>> @@ -139,20 +139,27 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
>>   existing:
>>          switch (state) {
>>          case RPMH_ACTIVE_ONLY_STATE:
>> -               if (req->sleep_val != UINT_MAX)
>> +               if (req->sleep_val != UINT_MAX) {
>>                          req->wake_val = cmd->data;
>> +                       ctrlr->dirty = true;
>> +               }
> Don't you need to set dirty = true for ACTIVE_ONLY state always? The
> conditional is just saying "if nobody set a sleep vote, then maintain
> this vote when we wake back up".

The ACTIVE_ONLY vote is cached as wake_val to be apply when wakeup happens.

In case value didn't change,wake_val is still same as older value and 
there is no need to mark the entire cache as dirty.

-- 
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