Messages in this thread | | | Subject | Re: [PATCH v2 0/3] media: vimc: Allow multiple capture devices to use the same sensor | From | Dafna Hirschfeld <> | Date | Tue, 28 Jul 2020 14:07:29 +0200 |
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Hi
On 28.07.20 13:39, Kaaira Gupta wrote: > On Mon, Jul 27, 2020 at 02:54:30PM -0300, Helen Koike wrote: >> Hi, >> >> On 7/27/20 11:31 AM, Kieran Bingham wrote: >>> Hi all, >>> >>> +Dafna for the thread discussion, as she's missed from the to/cc list. >>> >>> >>> On 24/07/2020 13:21, Kaaira Gupta wrote: >>>> On Fri, Jul 24, 2020 at 02:15:21PM +0200, Niklas Söderlund wrote: >>>> Hi, >>>> >>>>> Hi Kaaira, >>>>> >>>>> Thanks for your work. >>>> >>>> Thanks for yours :D >>>> >>>>> >>>>> On 2020-07-24 17:32:10 +0530, Kaaira Gupta wrote: >>>>>> This is version 2 of the patch series posted by Niklas for allowing >>>>>> multiple streams in VIMC. >>>>>> The original series can be found here: >>>>>> https://patchwork.kernel.org/cover/10948831/ >>>>>> >>>>>> This series adds support for two (or more) capture devices to be >>>>>> connected to the same sensors and run simultaneously. Each capture device >>>>>> can be started and stopped independent of each other. >>>>>> >>>>>> Patch 1/3 and 2/3 deals with solving the issues that arises once two >>>>>> capture devices can be part of the same pipeline. While 3/3 allows for >>>>>> two capture devices to be part of the same pipeline and thus allows for >>>>>> simultaneously use.
I wonder if these two patches are enough, since each vimc entity also have a 'process_frame' callback, but only one allocated frame. That means that the 'process_frame' can be called concurrently by two different streams on the same frame and cause corruption.
Thanks, Dafna
>>>>> >>>>> I'm just curious if you are aware of this series? It would replace the >>>>> need for 1/3 and 2/3 of this series right? >>>> >>>> v3 of this series replaces the need for 1/3, but not the current version >>>> (ie v4). v4 of patch 2/5 removes the stream_counter that is needed to >>>> keep count of the calls to s_stream. Hence 1/3 becomes relevant again. >>> >>> So the question really is, how do we best make use of the two current >>> series, to achieve our goal of supporting multiple streams. >>> >>> Having not parsed Dafna's series yet, do we need to combine elements of >>> both ? Or should we work towards starting with this series and get >>> dafna's patches built on top ? >>> >>> Or should patch 1/3 and 3/3 of this series be on top of Dafna's v4 ? >>> >>> (It might be noteworthy to say that Kaaira has reported successful >>> multiple stream operation from /this/ series and her development branch >>> on libcamera). >> >> Dafna's patch seems still under discussion, but I don't want to block progress in Vimc either. >> >> So I was wondering if we can move forward with Vimc support for multistreaming, >> without considering Dafna's patchset, and we can do the clean up later once we solve that. >> >> What do you think? > > I agree with supporting multiple streams with VIMC with this patchset, > and then we can refactor the counters for s_stream in VIMC later (over > this series) if dafna includes them in subsequent version of her patchset. >
I also think that adding support in the code will take much longer and should not stop us from supporting vimc independently.
Thanks, Dafna
>> >> Regards, >> Helen >> >>> >>> >>>>> 1. https://lore.kernel.org/linux-media/20200522075522.6190-1-dafna.hirschfeld@collabora.com/ >>>>> >>>>>> >>>>>> Changes since v1: >>>>>> - All three patches rebased on latest media-tree. >>>>>> Patch 3: >>>>>> - Search for an entity with a non-NULL pipe instead of searching >>>>>> for sensor. This terminates the search at output itself. >>>>>> >>>>>> Kaaira Gupta (3): >>>>>> media: vimc: Add usage count to subdevices >>>>>> media: vimc: Serialize vimc_streamer_s_stream() >>>>>> media: vimc: Join pipeline if one already exists >>>>>> >>>>>> .../media/test-drivers/vimc/vimc-capture.c | 35 ++++++++++++++++++- >>>>>> .../media/test-drivers/vimc/vimc-debayer.c | 8 +++++ >>>>>> drivers/media/test-drivers/vimc/vimc-scaler.c | 8 +++++ >>>>>> drivers/media/test-drivers/vimc/vimc-sensor.c | 9 ++++- >>>>>> .../media/test-drivers/vimc/vimc-streamer.c | 23 +++++++----- >>>>>> 5 files changed, 73 insertions(+), 10 deletions(-) >>>>>> >>>>>> -- >>>>>> 2.17.1 >>>>>> >>>>> >>>>> -- >>>>> Regards, >>>>> Niklas Söderlund >>>
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