From: Hans Verkuil <hverkuil@xs4all.nl>
To: Stanimir Varbanov <stanimir.varbanov@linaro.org>,
Malathi Gottam <mgottam@codeaurora.org>,
mchehab@kernel.org
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org, acourbot@chromium.org,
vgarodia@codeaurora.org, Tomasz Figa <tfiga@chromium.org>
Subject: Re: [PATCH v3] media: venus: amend buffer size for bitstream plane
Date: Mon, 26 Nov 2018 16:23:52 +0100 [thread overview]
Message-ID: <57b28a7f-8c5c-22d2-2f89-e6d6ebdcb8a2@xs4all.nl> (raw)
In-Reply-To: <f6106d20-abee-979c-8ac1-6c9115e8373c@linaro.org>
On 11/26/2018 03:57 PM, Stanimir Varbanov wrote:
> Hi Hans,
>
> On 11/26/18 3:37 PM, Hans Verkuil wrote:
>> On 11/26/2018 11:12 AM, Malathi Gottam wrote:
>>> Accept the buffer size requested by client and compare it
>>> against driver calculated size and set the maximum to
>>> bitstream plane.
>>>
>>> Signed-off-by: Malathi Gottam <mgottam@codeaurora.org>
>>
>> Sorry, this isn't allowed. It is the driver that sets the sizeimage value,
>> never the other way around.
>
> I think for decoders (OUTPUT queue) and encoders (CAPTURE queue) we
> allowed userspace to set sizeimage for buffers. See [1] Initialization
> paragraph point 2:
>
> ``sizeimage``
> desired size of ``CAPTURE`` buffers; the encoder may adjust it to
> match hardware requirements
>
> Similar patch we be needed for decoder as well.
I may have missed that change since it wasn't present in v1 of the stateful
encoder spec.
Tomasz, what was the reason for this change? I vaguely remember some thread
about this, but I forgot the details. Since this would be a departure of
the current API this should be explained in more detail.
I don't really see the point of requiring userspace to fill this in. For
stateful codecs it can just return some reasonable size. Possibly calculated
using the provided width/height values or (if those are 0) some default value.
Ditto for decoders.
Stanimir, I certainly cannot merge this until this has been fully nailed down
as it would be a departure from the current API.
And looking at the venus patch I do not see how it helps userspace.
Regards,
Hans
>
>>
>> If you need to allocate larger buffers, then use VIDIOC_CREATE_BUFS instead
>> of VIDIOC_REQBUFS.
>>
>> What problem are you trying to solve with this patch?
>>
>> Regards,
>>
>> Hans
>>
>
next prev parent reply other threads:[~2018-11-27 2:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 10:12 [PATCH v3] media: venus: amend buffer size for bitstream plane Malathi Gottam
2018-11-26 12:53 ` Stanimir Varbanov
2018-11-26 13:37 ` Hans Verkuil
2018-11-26 14:57 ` Stanimir Varbanov
2018-11-26 15:23 ` Hans Verkuil [this message]
2018-11-26 15:44 ` Tomasz Figa
2018-11-26 15:59 ` Hans Verkuil
2018-11-26 16:07 ` Tomasz Figa
2018-11-26 16:41 ` Hans Verkuil
2018-11-27 8:16 ` Alexandre Courbot
2018-11-28 8:41 ` Hans Verkuil
2018-11-27 8:23 ` Tomasz Figa
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