Guide to contribute to kernel video drivers

[Jean-Sébastien Pédron]

On 22/02/2016 12:21, Alexander Mishurov wrote:
> 1. Linux kpi is conflicting with drm_os_freebsd and drm_scatter and may
> be some other things from drm. This means we have to migrate whole drm
> core to linux kpi and therefore that affects at least radeon drivers.
> It's quite huge amount of work in comparison to only i915. What about
> existing non i915 drivers depend on drm and drm_os_freebsd ?

The whole DRM needs to be moved to linuxkpi, not just a driver. Some
interfaces will change in the process and we must keep DRM components
consistent.

> 2. Move to linux kpi is not enough, I'm sure there should be one more
> layer like drm_os_freebsd on top of linux kpi with our own macros,
> inlines and other things for minimizing modifications of the original
> Linux driver sources because linux kpi covers only basic things.

No, I believe if linuxkpi misses something, it should be added there,
not in an additional wraper.

The goal is not to eliminate completely the diff with Linux. For
instance, the integration with the VM won't be abstracted: the Linux VM
and the FreeBSD vm work differently. This must be reflected into DRM.

Another one is I²C. FreeBSD and Linux' I²C subsystems have incompatible
design and API. Unlike the VM however, this looks more like a pain point
:) In the beginning, we will keep the I²C calls unabstracted, but in the
long term, it would be nice to add a Linux API wrapper to our I²C
subsystem, if it's possible.

-- 
Jean-Sébastien Pédron

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