[Arm-netbook] EOMA Specification / Documentation Issues

[mike.valk at gmail.com]

2016-09-24 5:27 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:

<SNIP>

>
>
> > Let's switch to the Pocket QWERTY Computer as an example instead of
> router. The A20 cpu card ships with Parabola, a desktop/workstation style
> OS. I want my customers to have a good experience when they use my handheld
> housing. Using an OS tailored for desktop/workstation computing is *not* a
> good experience on a small screen (I've tried this with the Zipit and it
> "worked", but was not very productive). I can make this transition even
> *easier* for average consumer by supplying a SD card with Replicant or some
> other custom libre distribution designed for small screens.
>
> or, you could supply multiple OS SD cards for them, and set up the
> NAND to look an OS on the A20's MicroSD Card slot.
>
> yes, i'm keenly aware that the alteration of the OS to suit LCD size
> is a Big Deal.  putting it another way: it's a PAIN IN THE ASS! :)
>
> it's made even more complicated (for the A20) by the fact that the
> people who did the sunxi u-boot and mainline kernel didn't think about
> this in advance: they've specified that the LCD shall be set up by
> u-boot and u-boot alone, leaving absolutely no possibility for
> changing the LCD size without a total reboot!  oops...
>

Not quite sure that is the case. U-Boot provides "early" setup, regulator
and clocks etc., for u-boot output. SimpleFB takes over the settings from
U-Boot (via u-boot modified device-tree). But a proper KMS/DRM driver
(sunxi has something working for A13, H3, A33) may change all that. Too bad
that libv got burned and refused to release his work.
https://lkml.org/lkml/2015/10/30/358
http://linux-sunxi.org/Linux_mainlining_effort

So yeah for SimpleFB you're bound to change the display settings in advance
of a (re)boot. To the specific device. With proper KMS not.

Which leads to the EOMA68 minimum allowed display resolution should be set
in U-Boot.


<snip>
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