From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Verkuil Subject: Re: [PATCH v4 3/5] staging: Introduce NVIDIA Tegra video decoder driver Date: Tue, 5 Dec 2017 14:03:37 +0100 Message-ID: <93c98569-0282-80d9-78ad-c8ab8fd9db92@xs4all.nl> References: <1a3798f337c0097e67d70226ae3ba665fd9156c2.1508448293.git.digetx@gmail.com> <3ac6a087-def2-014f-673d-1be9d5094635@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3ac6a087-def2-014f-673d-1be9d5094635@gmail.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: Dmitry Osipenko , Thierry Reding , Jonathan Hunter , Greg Kroah-Hartman , Rob Herring , Mauro Carvalho Chehab , Stephen Warren , Vladimir Zapolskiy Cc: devel@driverdev.osuosl.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, Maxime Ripard , Giulio Benetti , Dan Carpenter , linux-media@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On 12/05/17 13:17, Dmitry Osipenko wrote: > Hi Hans, > > On 04.12.2017 17:04, Hans Verkuil wrote: >> Hi Dmitry, >> >> As you already mention in the TODO, this should become a v4l2 codec driver. >> >> Good existing examples are the coda, qcom/venus and mtk-vcodec drivers. >> >> One thing that is not clear from this code is if the tegra hardware is a >> stateful or stateless codec, i.e. does it keep track of the decoder state >> in the hardware, or does the application have to keep track of the state and >> provide the state information together with the video data? >> >> I ask because at the moment only stateful codecs are supported. Work is ongoing >> to support stateless codecs, but we don't support that for now. >> > > It is stateless. Is there anything ready to try out? If yes, could you please > give a reference to that work? I rebased my two year old 'requests2' branch to the latest mainline version and gave it the imaginative name 'requests3': https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=requests3 (Note: only compile tested!) This is what ChromeOS has been using (actually they use a slightly older version) and the new version that is currently being developed will be similar, so any work you do on top of this will carry over to the final version without too much effort. At least, that's the intention :-) I've CC-ed Maxime and Giulio as well: they are looking into adding support for the stateless allwinner codec based on this code as well. There may well be opportunities for you to work together, esp. on the userspace side. Note that Rockchip has the same issue, they too have a stateless HW codec. > >> Anyway, I'm OK with merging this in staging. Although I think it should go >> to staging/media since we want to keep track of it. >> > > Awesome, I'll move driver to staging/media in V5. Thanks! Nice, thanks! Hans From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752819AbdLENDr (ORCPT ); Tue, 5 Dec 2017 08:03:47 -0500 Received: from lb3-smtp-cloud7.xs4all.net ([194.109.24.31]:37276 "EHLO lb3-smtp-cloud7.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752042AbdLENDp (ORCPT ); Tue, 5 Dec 2017 08:03:45 -0500 Subject: Re: [PATCH v4 3/5] staging: Introduce NVIDIA Tegra video decoder driver To: Dmitry Osipenko , Thierry Reding , Jonathan Hunter , Greg Kroah-Hartman , Rob Herring , Mauro Carvalho Chehab , Stephen Warren , Vladimir Zapolskiy Cc: Dan Carpenter , linux-media@vger.kernel.org, linux-tegra@vger.kernel.org, devel@driverdev.osuosl.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Maxime Ripard , Giulio Benetti References: <1a3798f337c0097e67d70226ae3ba665fd9156c2.1508448293.git.digetx@gmail.com> <3ac6a087-def2-014f-673d-1be9d5094635@gmail.com> From: Hans Verkuil Message-ID: <93c98569-0282-80d9-78ad-c8ab8fd9db92@xs4all.nl> Date: Tue, 5 Dec 2017 14:03:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <3ac6a087-def2-014f-673d-1be9d5094635@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4wfCAVSAQlCGrUqVEM7KBWS3rz1uc1vvgIO0cdNgi7qXAeP05JOZfvO1/+LZVHwOTxmfTKPZwAfY0IA3DkvZ4KHTU/Q2ohqKsJQ7wKHbsdayfa/MQjOeNi 5KVAGiZ5Q+TZtC1BcCUd5HzGRB+SYlr2uy+KI8DWpfoOjpK2vw0CB+mMMJGgVW16mi7vVJoC873JiD9kOmefKH+58IT5eqPzXcMPeHvihanA+wTQNwq4rBDu 0wJjSXrzEg5Rjyh2bkeJQ/MMFFEAPD8KhAyNWI0DHvZe9pRVLxFihn7sBwPAms9vjyuj/6SV+e6z3j+l55D8+S802KIXf5TENQghu8rmdNy4/rQiyKo4f7Ae ZhnwP9neCSO4GwwQM3EMqG9iqH+16seUJz+DL3EsXcXNc8Gqbe1BcZOCvCvQeX9XDrMrcNDtsLbDVJ57CDTH4SMfA7XtL81prMJLR3xzy0l7Xcp+nHCtbtsN Nvt+oVPyJwtqD4SzYmWkKuQ5wTQs+IsRkNElqCKwKJ2Y/h13r8H7gE9iOgi/luwAbLumopTXb2KCJcIpnDD2CEmJ5IhkStx5ox/o4Fo85/3UlPnpwgL40W0D 0x40fXnGKLugMdAbTz0z0hDZA+01TfVJuLOkSi9Qxtt2xh0Z7OhxjDH5SGYhdavPh2kOyEtTI1z/Yljp107zTu54 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/05/17 13:17, Dmitry Osipenko wrote: > Hi Hans, > > On 04.12.2017 17:04, Hans Verkuil wrote: >> Hi Dmitry, >> >> As you already mention in the TODO, this should become a v4l2 codec driver. >> >> Good existing examples are the coda, qcom/venus and mtk-vcodec drivers. >> >> One thing that is not clear from this code is if the tegra hardware is a >> stateful or stateless codec, i.e. does it keep track of the decoder state >> in the hardware, or does the application have to keep track of the state and >> provide the state information together with the video data? >> >> I ask because at the moment only stateful codecs are supported. Work is ongoing >> to support stateless codecs, but we don't support that for now. >> > > It is stateless. Is there anything ready to try out? If yes, could you please > give a reference to that work? I rebased my two year old 'requests2' branch to the latest mainline version and gave it the imaginative name 'requests3': https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=requests3 (Note: only compile tested!) This is what ChromeOS has been using (actually they use a slightly older version) and the new version that is currently being developed will be similar, so any work you do on top of this will carry over to the final version without too much effort. At least, that's the intention :-) I've CC-ed Maxime and Giulio as well: they are looking into adding support for the stateless allwinner codec based on this code as well. There may well be opportunities for you to work together, esp. on the userspace side. Note that Rockchip has the same issue, they too have a stateless HW codec. > >> Anyway, I'm OK with merging this in staging. Although I think it should go >> to staging/media since we want to keep track of it. >> > > Awesome, I'll move driver to staging/media in V5. Thanks! Nice, thanks! Hans