From: Alexandre Courbot <acourbot@chromium.org>
To: Nicolas Dufresne <nicolas@ndufresne.ca>
Cc: Stanimir Varbanov <stanimir.varbanov@linaro.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
linux-arm-msm@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] media: venus: fix reported size of 0-length buffers
Date: Wed, 14 Nov 2018 13:12:46 +0900 [thread overview]
Message-ID: <CAPBb6MWJ1Qu9YoRRusOGiC7dioMkgvU=1dCF6XZ4xDUxp7ri9A@mail.gmail.com> (raw)
In-Reply-To: <CAKQmDh-91tHP1VxLisW1A3GR9G7du3F-Y2XrrgoFU=gvhGoP6w@mail.gmail.com>
On Wed, Nov 14, 2018 at 3:54 AM Nicolas Dufresne <nicolas@ndufresne.ca> wrote:
>
>
>
> Le mar. 13 nov. 2018 04 h 30, Alexandre Courbot <acourbot@chromium.org> a écrit :
>>
>> The last buffer is often signaled by an empty buffer with the
>> V4L2_BUF_FLAG_LAST flag set. Such buffers were returned with the
>> bytesused field set to the full size of the OPB, which leads
>> user-space to believe that the buffer actually contains useful data. Fix
>> this by passing the number of bytes reported used by the firmware.
>
>
> That means the driver does not know on time which one is last. Why not just returned EPIPE to userspace on DQBUF and ovoid this useless roundtrip ?
Sorry, I don't understand what you mean. EPIPE is supposed to be
returned after a buffer with V4L2_BUF_FLAG_LAST is made available for
dequeue. This patch amends the code that prepares this LAST-flagged
buffer. How could we avoid a roundtrip in this case?
>
>>
>> Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
>> ---
>> drivers/media/platform/qcom/venus/vdec.c | 4 +---
>> 1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
>> index 189ec975c6bb..282de21cf2e1 100644
>> --- a/drivers/media/platform/qcom/venus/vdec.c
>> +++ b/drivers/media/platform/qcom/venus/vdec.c
>> @@ -885,10 +885,8 @@ static void vdec_buf_done(struct venus_inst *inst, unsigned int buf_type,
>> vbuf->field = V4L2_FIELD_NONE;
>>
>> if (type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
>> - unsigned int opb_sz = venus_helper_get_opb_size(inst);
>> -
>> vb = &vbuf->vb2_buf;
>> - vb2_set_plane_payload(vb, 0, bytesused ? : opb_sz);
>> + vb2_set_plane_payload(vb, 0, bytesused);
>> vb->planes[0].data_offset = data_offset;
>> vb->timestamp = timestamp_us * NSEC_PER_USEC;
>> vbuf->sequence = inst->sequence_cap++;
>> --
>> 2.19.1.930.g4563a0d9d0-goog
>>
next prev parent reply other threads:[~2018-11-14 14:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-13 9:30 [PATCH] media: venus: fix reported size of 0-length buffers Alexandre Courbot
[not found] ` <CAKQmDh-91tHP1VxLisW1A3GR9G7du3F-Y2XrrgoFU=gvhGoP6w@mail.gmail.com>
2018-11-14 4:12 ` Alexandre Courbot [this message]
2018-11-15 16:49 ` Nicolas Dufresne
2018-11-15 16:51 ` Nicolas Dufresne
2018-11-16 4:08 ` Tomasz Figa
2018-11-22 8:31 ` Alexandre Courbot
2018-11-22 23:53 ` Nicolas Dufresne
2018-11-26 8:23 ` Alexandre Courbot
2018-11-26 8:54 ` Stanimir Varbanov
2018-11-26 9:45 ` Stanimir Varbanov
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