Re: [PATCH] media: venus: support frame rate control

From: Stanimir Varbanov <stanimir.varbanov@linaro.org>
To: Jeffrey Kardatzke <jkardatzke@google.com>,
	Stanimir Varbanov <stanimir.varbanov@linaro.org>
Cc: linux-media@vger.kernel.org, Andy Gross <agross@kernel.org>,
	"Mauro Carvalho Chehab )" <mchehab@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] media: venus: support frame rate control
Date: Wed, 19 Feb 2020 09:56:27 +0200	[thread overview]
Message-ID: <b0c8653a-314e-bab9-9dc8-8c33b8d1efc9@linaro.org> (raw)
In-Reply-To: <CA+ddPcPjtv_9s4+t_1jkoGSZihVu2cVLyW102WuoLMy-RGkKPw@mail.gmail.com>

Hi Jeff,

On 2/18/20 9:09 PM, Jeffrey Kardatzke wrote:
> Sorry for the duplicate, accidentally used HTML format and it got
> bounced from the mailing lists so resending.
> 
> On Mon, Feb 17, 2020 at 2:15 AM Stanimir Varbanov
> <stanimir.varbanov@linaro.org> wrote:
>>
>> Hi Jeff,
>>
>> Thanks for the patch!
>>
>> On 2/13/20 11:30 PM, Jeffrey Kardatzke wrote:
>>> Frame rate control is always enabled in this driver, so make it silently
>>> support the V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE.
>>>
>>> Signed-off-by: Jeffrey Kardatzke <jkardatzke@google.com>
>>> ---
>>>  drivers/media/platform/qcom/venus/venc_ctrls.c | 6 ++++++
>>>  1 file changed, 6 insertions(+)
>>>
>>> diff --git a/drivers/media/platform/qcom/venus/venc_ctrls.c b/drivers/media/platform/qcom/venus/venc_ctrls.c
>>> index 877c0b3299e9..9ede692f77c5 100644
>>> --- a/drivers/media/platform/qcom/venus/venc_ctrls.c
>>> +++ b/drivers/media/platform/qcom/venus/venc_ctrls.c
>>> @@ -199,6 +199,9 @@ static int venc_op_s_ctrl(struct v4l2_ctrl *ctrl)
>>>               }
>>>               mutex_unlock(&inst->lock);
>>>               break;
>>> +     case V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE:
>>> +             // Silently ignore, it's always enabled.
>>
>> Please, use C comments and follow the kernel coding style.
> 
> OK, hopefully I've got that now. I didn't see any issues aside from
> the comment style though.
> I'll upload a new patch shortly.
>>
>>
>> I wonder shouldn't it be better to add rc_enable field in struct
>> venc_controls and give the user choice to disable the rate control? We
>> can keep the default to be "enabled".
>>
> That'd be fine. Is there a way to actually disable the rate control though?

The rate control property values are here [1], and [2] is where we set
the control.

-- 
regards,
Stan

[1]
https://elixir.bootlin.com/linux/v5.6-rc2/source/drivers/media/platform/qcom/venus/hfi_helper.h#L229
[2]
https://elixir.bootlin.com/linux/v5.6-rc2/source/drivers/media/platform/qcom/venus/venc.c#L734