[fedora-arm] 1ghz ARM Laptop (12in 1280x800 LCD)

[Gordan Bobic]

Luke Kenneth Casson Leighton wrote:

>> Can you
>> point me at the relevant bit of the kernel code?
> 
>  aw gawd come on, gordan :)

The point I was getting at is that the Tegra FB driver doesn't do this 
at all. It's very minimalistic.

>> If you're right, then a
>> 720p panel may not be implausible. But my understanding is that the screen
>> gets setup by the boot loader, and the Tegra FB driver just works based on
>> that, it doesn't configure anything itself.
> 
>  hmmm, that sounds about right.  and if you don't mind a bit of
> "bzzzt" and not being able to see anything during the boot process,
> you should be able to overwrite whatever crud settings the bootloader
> decided to set, once you've started the linux kernel.
> 
>  the tegra fb kernel driver _should_ be setting them anyway.

I'll take another look, but I'm 99% certain it doesn't. And my post to 
the nvidia tegra developer forum regarding this went predictably unanswered.

>> The latter may be difficult
>> given that nvidia aren't exactly renowned for publishing their specs.
> 
>  it's nothing to do with nvidia, and everything to do with the timings
> of the LCD.  ahh, i see what you mean, you'd need to know where the
> registers are for blopping in the hsync, vsync etc. etc. timings.

That's what I'm talking about.

>  yep, you're right. *sigh* that'll need investigating.
> 
>  ok - start here.
> https://alioth.debian.org/plugins/scmgit/cgi-bin/gitweb.cgi

You're missing the point - there is no code that does the screen 
geometry setup already available that I'm aware of. The really shocking 
part is that the binary closed-source Xorg driver doesn't handle EDID 
either. Or rather - it _does_ (it's reported on Xorg.log) - but it is 
always the same regardless of the panel used. So either it is hard-coded 
in the driver or it is somewhere sufficiently low-level to intercept and 
override what comes back from the panel.

Gordan