linux-kernel - Re: [PATCH 10/28] venus: vdec: call session

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Date:   Thu, 3 May 2018 14:36:54 +0300
From:   Stanimir Varbanov <stanimir.varbanov@...aro.org>
To:     Vikash Garodia <vgarodia@...eaurora.org>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hverkuil@...all.nl>, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-media-owner@...r.kernel.org
Subject: Re: [PATCH 10/28] venus: vdec: call session_continue in insufficient
 event

Hi Vikash,

Thanks for the comments!

On  2.05.2018 09:26, Vikash Garodia wrote:
> Hello Stanimir,
> 
> On 2018-04-24 18:14, Stanimir Varbanov wrote:
>> Call session_continue for Venus 4xx version even when the event
>> says that the buffer resources are not sufficient. Leaving a
>> comment with more information about the workaround.
>>
>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@...aro.org>
>> ---
>>  drivers/media/platform/qcom/venus/vdec.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/media/platform/qcom/venus/vdec.c
>> b/drivers/media/platform/qcom/venus/vdec.c
>> index c45452634e7e..91c7384ff9c8 100644
>> --- a/drivers/media/platform/qcom/venus/vdec.c
>> +++ b/drivers/media/platform/qcom/venus/vdec.c
>> @@ -873,6 +873,14 @@ static void vdec_event_notify(struct venus_inst
>> *inst, u32 event,
>>
>>              dev_dbg(dev, "event not sufficient resources (%ux%u)\n",
>>                  data->width, data->height);
>> +            /*
>> +             * Workaround: Even that the firmware send and event for
>> +             * insufficient buffer resources it is safe to call
>> +             * session_continue because actually the event says that
>> +             * the number of capture buffers is lower.
>> +             */
>> +            if (IS_V4(core))
>> +                hfi_session_continue(inst);
>>              break;
>>          case HFI_EVENT_RELEASE_BUFFER_REFERENCE:
>>              venus_helper_release_buf_ref(inst, data->tag);
> 
> Insufficient event from video firmware could be sent either,
> 1. due to insufficient buffer resources
> 2. due to lower capture buffers
> 
> It cannot be assumed that the event received by the host is due to lower 
> capture
> buffers. Incase the buffer resource is insufficient, let say there is a 
> bitstream
> resolution switch from 720p to 1080p, capture buffers needs to be 
> reallocated.

I agree with you. I will rework this part and call session_continue only 
for case #2.

> 
> The driver should be sending the V4L2_EVENT_SOURCE_CHANGE to client 
> instead of ignoring
> the event from firmware.

The v4l2 event is sent always to v4l clients.

regards,
Stan