HDMI support on Allwinner A64

[Gary Otten]

My questions are these?

How far can efifb driver/support take me? It displayed the console with the
addition
of hw.regulator.disable_unused=0  to loader.conf

Will it be possible to run Xwindows with efifb driver/support ?

The link for the DRM driver is broken, has this driver been completed, if
not how useful will it be compared to the efifb driver/support?  Where can
I find the DRM driver?


The below is the research I have done.
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I saw a posting from June 2019 in this list.

Milan Obouch came up with the idea to keep power going to output buffer.
...............
Milan Writes

which makes me think, together with presence of getty processes
attached to /dev/ttyvN devices, that all what's missing is just
physical video output signal, and this is most probably caused by
output buffer being shut down. So I googled a bit and found a hint,
tried it - I put line

hw.regulator.disable_unused=0

into /boot/loader.conf file and it works. I think it just uses HDMI
output engine configured by u-boot instead of configuring it itself, as
we have no driver for hdmi and hdmi-phy devices on A64 SoCs.

*Adding the above to the loader.conf did keep the HDMI output alive, thus
keeping the console displayed.

Emmanuel Vadot writes
.............
No, A64 uses the version 2 of the Allwinner display engine, I have a
DRM driver working for it (but still have some work to do on it).
https://github.com/evadot/freebsd/tree/drm_aw_de2  (Link now broken)

I also reviewed The paper by Emmanuel Vadot
https://papers.freebsd.org/2019/asiabsdcon/vadot-adventure_in_drmland/
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