Hi all,
I'd like to discuss Exynos DRM TODO work.
There are features we have to solve and implement. The purpose of this email is to share what we have to do so that other guys can be involved without duplicated work.
1. gscaler based on KMS interfaces - exynos5250 and later use the gscaler device instead of VP device. And now exynos drm driver has gscaler module as a sub module of IPP framework. However, this gscaler module is very specific to IPP framework so it's not easy to reuse this module. So maybe we need so many works for it.
Video play back path using post process (AS IS): MFC--------IPP--------KMS---------FIMD or HDMI
Ideal video play back path using post process (TO BE): MFC--------KMS--------FIMD or HDMI
The above scenario is to send decoded image data (YUV format) to display device via post process. However, we don't really need to use IPP framework in case of using gscaler as VP. All we have to do is to call kms interface (setplane) for it like we did before.
2. More features for HDMI sound support - we need to implement Exynos ALSA SoC DAI driver for HDMI audio (CPU DAI and CODEC DAI). Sampling freq, bit rate, and so on from user side should be sent to drm hdmi driver via ALSA interface and the ALSA SoC DAI driver. As of now, it seems like that we should implement this driver like OMAP does because there is no common framework for interfacing between ALSA SoC DAI driver and DRM HDMI driver: in case of OMAP, it seems like that ALSA SoC audio driver calls interfaces of DSS driver directly. I think we could implement ALSA SoC DAI driver in more generic way if we first implement common framework for it.
Welcome to any volunteer and other opinions.
Thanks, Inki Dae