Re: [PATCH v6 2/4] media: venus: pm_helpers: use opp-table for the frequency

[Konrad Dybcio]

On 4/7/25 5:39 PM, Bryan O'Donoghue wrote:
> On 09/01/2025 13:05, Konrad Dybcio wrote:
>> On 2.01.2025 6:38 AM, Renjiang Han wrote:
>>>
>>> On 12/23/2024 10:17 PM, Konrad Dybcio wrote:
>>>> On 19.12.2024 6:41 AM, Renjiang Han wrote:
>>>>> The frequency value in the opp-table in the device tree and the freq_tbl
>>>>> in the driver are the same.
>>>>>
>>>>> Therefore, update pm_helpers.c to use the opp-table for frequency values
>>>>> for the v4 core.
>>>>> If getting data from the opp table fails, fall back to using the frequency
>>>>> table.
>>>>>
>>>>> Signed-off-by: Renjiang Han<quic_renjiang@xxxxxxxxxxx>
>>>>> ---
>>>>>    drivers/media/platform/qcom/venus/pm_helpers.c | 53 +++++++++++++++++++-------
>>>>>    1 file changed, 39 insertions(+), 14 deletions(-)
>>>>>
>>>>> diff --git a/drivers/media/platform/qcom/venus/pm_helpers.c b/drivers/media/platform/qcom/venus/pm_helpers.c
>>>>> index 33a5a659c0ada0ca97eebb5522c5f349f95c49c7..b61c0ad152878870b7223efa274e137d3636433b 100644
>>>>> --- a/drivers/media/platform/qcom/venus/pm_helpers.c
>>>>> +++ b/drivers/media/platform/qcom/venus/pm_helpers.c
>>>>> @@ -43,14 +43,20 @@ static int core_clks_enable(struct venus_core *core)
>>>>>        const struct venus_resources *res = core->res;
>>>>>        const struct freq_tbl *freq_tbl = core->res->freq_tbl;
>>>>>        unsigned int freq_tbl_size = core->res->freq_tbl_size;
>>>>> +    struct device *dev = core->dev;
>>>>> +    struct dev_pm_opp *opp;
>>>>>        unsigned long freq;
>>>>>        unsigned int i;
>>>>>        int ret;
>>>>>    -    if (!freq_tbl)
>>>>> -        return -EINVAL;
>>>>> -
>>>>> -    freq = freq_tbl[freq_tbl_size - 1].freq;
>>>>> +    opp = dev_pm_opp_find_freq_ceil(dev, &freq);
>>>>> +    if (IS_ERR(opp)) {
>>>>> +        if (!freq_tbl)
>>>>> +            return -EINVAL;
>>>>> +        freq = freq_tbl[freq_tbl_size - 1].freq;
>>>>> +    } else {
>>>>> +        dev_pm_opp_put(opp);
>>>>> +    }
>>>> I'm not super convinced how this could have ever worked without
>>>> scaling voltage levels, by the way. Perhaps this will squash some
>>>> random bugs :|
>>>>
>>>> Konrad
>>>   Thanks for your comment.
>>>   The default value of freq is 0, and then dev_pm_opp_find_freq_ceil is
>>>   used to match freq to the maximum value in opp-table that is close to
>>>   0. The frequency values ​​in opp-table and freq_tbl are the same, and
>>>   dev_pm_opp_find_freq_ceil is used to assign the minimum value in
>>>   opp-table to freq. So the logic is the same as before. I'm not sure if
>>>   I've answered your concern.
>>
>> We talked offline, but for the record: my concern here was about
>> clk_set_rate() not scaling RPM/h voltage corners, which this patch
>> fixes
>>
>> Konrad
> 
> Konrad is this an RB from you, do you have any other concerns with this code ?

OK the comment above was misleading - back then I must have thought this patch
changed clk_set_rate to dev_pm_opp_set_rate - which is not what it does

I won't be blocking this, but I'm not super keen on thoroughly reviewing it
either - there are a lot of raw clk_ calls that are hard to keep track of.. 

Konrad