On Thu, Aug 25, 2016 at 08:45:25PM +0900, Inki Dae wrote: > > > 2016년 08월 25일 17:42에 Daniel Vetter 이(가) 쓴 글: > > On Thu, Aug 25, 2016 at 05:06:55PM +0900, Inki Dae wrote: > >> > >> > >> 2016년 08월 24일 20:57에 Daniel Vetter 이(가) 쓴 글: > >>> On Wed, Aug 24, 2016 at 08:44:24PM +0900, Inki Dae wrote: > >>>> Hi, > >>>> > >>>> 2016년 08월 23일 18:41에 Daniel Stone 이(가) 쓴 글: > >>>>> Hi, > >>>>> > >>>>> On 22 August 2016 at 16:23, Rob Clark <robdclark@xxxxxxxxx> wrote: > >>>>>> I guess a lot comes down to 'how long before hw designers bolt a CP to > >>>>>> the thing'.. at that point, I think you especially don't want a > >>>>>> per-blit kernel interface. > >>>>> > >>>>> Regardless of whether or not we want it, we already _have_ it, in the > >>>>> form of V4L2 M2M. There are already a few IP blocks working on that, I > >>>>> believe. If V4L2 <-> KMS interop is painful, well, we need to fix that > >>>>> anyway ... > >>>> > >>>> So we are trying this. We had expereneced using V4L2 and DRM together on > >>>> Linux Platform makes it too complicated, and also integrated DRM with > >>>> M2M such as 2D and Post processor makes it simplified. So We have been > >>>> trying to move existing V4L2 based drivers into DRM excepting HW Video > >>>> Codec - called it MFC - and Camera sensor and relevant things. > >>>> I think now V4L2 and DRM frameworks may make many engineers confusing > >>>> because there are the same devices which can be controlled by V4L2 and > >>>> DRM frameworks - maybe we would need more efforts like Laurent did with > >>>> Live source[1] in the future. > >>> > >>> Can you pls explain in more detail where working with both v4l and drm > >>> drivers and making them cooperate using dma-bufs poses problems? We should > >>> definitely fix that. > >> > >> I think it would be most Linux Platforms - Android, Chrome and Tizen - > >> which would use OpenMAX/GStreammer for Multimedia and X or > >> Wayland/SurfaceFlinger for Display. > > > > Yes, that's the use case. Where is the problem in making this happen? v4l > > can import dma-bufs, drm can export them, and there's plenty devices > > shipping (afaik) that make use of exact this pipeline. Can you pls explain > > what problem you've hit trying to make this work on exynos? > > No problem but just make it complicated as I mentioned above - the > stream operations - S_FMT, REQBUF, QUARYBUF, QBUF, STREAM ON and DQBUF > of V4L2 would never be simple as DRM. Do you think M2M device should be > controlled by V4L2 interfaces? and even 2D accelerator? As long as I > know, The Graphics card on Desktop has all devices such as 2D/3D GPU, HW > Video codec and Display controller, and these devices are controlled by > DRM interfaces. So we - ARM Exynos - are trying to move these things to > DRM world and also trying to implement more convenient interfaces like > Marek did. This is a misconception, there's nothing in the drm world requiring that everything is under the same drm device. All the work we've done over the past years (dma-buf, reservations, fence, prime, changes in X.org and wayland) are _all_ to make it possible to have a gfx device consisting of multiple drm/v4l/whatever else nodes. Especially for a SoC moving back to fake-integrating stuff really isn't a good idea I think. And wrt drm being simpler than v4l - I don't think drm is any simpler, at elast if you look at some of the more feature-full render drivers. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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