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Subject: Re: [PATCH] media: venus: preserve DRC state across seeks
To:     Alexandre Courbot <acourbot@chromium.org>
Cc:     Linux Media Mailing List <linux-media@vger.kernel.org>,
        linux-arm-msm@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
References: <20201202053424.3286774-1-acourbot@chromium.org>
 <CAPBb6MXt4uL+VgxQs6ynf5LKae657QXmrjw6XYnL0vg_zuuDsw@mail.gmail.com>
From:   Stanimir Varbanov <stanimir.varbanov@linaro.org>
Message-ID: <89086086-c0d9-62b0-2819-a537fe92782f@linaro.org>
Date:   Wed, 2 Dec 2020 12:28:03 +0200
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Hi,

On 12/2/20 12:24 PM, Alexandre Courbot wrote:
> On Wed, Dec 2, 2020 at 2:34 PM Alexandre Courbot <acourbot@chromium.org> wrote:
>>
>> DRC events can happen virtually at anytime, including when we are
>> starting a seek. Should this happen, we must make sure to return to the
>> DRC state, otherwise the firmware will expect buffers of the new
>> resolution whereas userspace will still work with the old one.
>>
>> Returning to the DRC state upon resume for seeking makes sure that the
>> client will get the DRC event and will reallocate the buffers to fit the
>> firmware's expectations.
> 
> Oops, please ignore as this seems to depend on another patch... I will
> repost once I can figure out the correct dependency chain, unless
> Stanimir can find a better way to handle DRC during seek and flush.

This patch depends on [1] series which is still under review.

[1] https://www.spinics.net/lists/linux-media/msg177801.html

> 
>>
>> Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
>> ---
>>  drivers/media/platform/qcom/venus/vdec.c | 11 +++++++++--
>>  1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
>> index 8488411204c3..e3d0df7fd765 100644
>> --- a/drivers/media/platform/qcom/venus/vdec.c
>> +++ b/drivers/media/platform/qcom/venus/vdec.c
>> @@ -972,7 +972,10 @@ static int vdec_start_output(struct venus_inst *inst)
>>
>>         if (inst->codec_state == VENUS_DEC_STATE_SEEK) {
>>                 ret = venus_helper_process_initial_out_bufs(inst);
>> -               inst->codec_state = VENUS_DEC_STATE_DECODING;
>> +               if (inst->next_buf_last)
>> +                       inst->codec_state = VENUS_DEC_STATE_DRC;
>> +               else
>> +                       inst->codec_state = VENUS_DEC_STATE_DECODING;
>>                 goto done;
>>         }
>>
>> @@ -1077,8 +1080,10 @@ static int vdec_stop_capture(struct venus_inst *inst)
>>                 ret = hfi_session_flush(inst, HFI_FLUSH_ALL, true);
>>                 fallthrough;
>>         case VENUS_DEC_STATE_DRAIN:
>> -               vdec_cancel_dst_buffers(inst);
>>                 inst->codec_state = VENUS_DEC_STATE_STOPPED;
>> +               fallthrough;
>> +       case VENUS_DEC_STATE_SEEK:
>> +               vdec_cancel_dst_buffers(inst);
>>                 break;
>>         case VENUS_DEC_STATE_DRC:
>>                 WARN_ON(1);
>> @@ -1102,6 +1107,7 @@ static int vdec_stop_output(struct venus_inst *inst)
>>         case VENUS_DEC_STATE_DECODING:
>>         case VENUS_DEC_STATE_DRAIN:
>>         case VENUS_DEC_STATE_STOPPED:
>> +       case VENUS_DEC_STATE_DRC:
>>                 ret = hfi_session_flush(inst, HFI_FLUSH_ALL, true);
>>                 inst->codec_state = VENUS_DEC_STATE_SEEK;
>>                 break;
>> @@ -1371,6 +1377,7 @@ static void vdec_event_change(struct venus_inst *inst,
>>                         dev_dbg(dev, VDBGH "flush output error %d\n", ret);
>>         }
>>
>> +       inst->next_buf_last = true;
>>         inst->reconfig = true;
>>         v4l2_event_queue_fh(&inst->fh, &ev);
>>         wake_up(&inst->reconf_wait);
>> --
>> 2.29.2.454.gaff20da3a2-goog
>>

-- 
regards,
Stan