[Letux-kernel] [small team RFC v3 00/10] Make use of TILER for OMAP5/Pyra LCD

H. Nikolaus Schaller hns at goldelico.com
Tue Feb 6 09:40:02 CET 2018


Hi,

> Am 06.02.2018 um 07:03 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> Hi,
> 
> On Mon,  5 Feb 2018 17:20:55 +0100
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> This patch set seems to be required to form a practical solution for the OMAP5 based Pyra.
>> 
>> What we need is to rotate the LCD on the MIPI port for X11/DRM/FB by 90 degrees
>> because it is a portrait display installed in landscape rotation.
>> 
>> This should either be done by xrandr/xorg.conf and/or some module parameter during
>> boot.
>> 
>> Independently, we also should be able to support xrandr on the HDMI port.
>> 
>> We only need this on OMAP5 Pyra, not on OMAP3 devices like OpenPandora or GTA04.
>> 
>> Since we have a multi-arch kernel the solution should not explicitly depend on
>> the SoC we use or force to config for a specific SOC.
>> 
>> At the moment this is partially a hack to make it working but some patches even
>> miss signed-offs. So let's start to discuss them and improve until we can submit
>> this work for review by a broader public (LKML).
>> 
> 
>> Andreas Kemnade (1):
>>  omapdrm: try to allocate non-tiled buffer object if tiled fails
>> 
> For reviewing (and bisect-ability) it would be easier to have this
> squashed with omapdrm: allocate fbdev in TILER.

In the long run, yes.

At the moment I did not want to squash patches from different authors,
especially as "omapdrm: allocate fbdev in TILER" does not yet
have a signed-off.

> 
> Another question:
> Sebastian Reichel showed a rotated console on omap4 in his
> fosdem presentation, so can we do it the same way?

Interesting.

Well, we can do it the same way if we know the way he is doing it.
Did he share any details? Or a pointer to the code doing this?

I think this TILER patch set can do the same (on OMAP5) if rotation
is initialized earlier. During LetuxOS boot some blinking cursor appears
unrotated.

Then LetuxOS user-space runs our tiler-ctl script and rotates by 270 degrees.
After that the blinking cursor is correctly rotated until it is replaced
by X11.

So I think by enabling console and doing the setup earlier it could do that.

> As it rotated hdmi and lcd the same time it does not look like something
> done in a lcd driver chip...

Maybe he is swapping x and y coordinates when changing pixels in the shared fb.
But that does not solve all rotation problems, especially for software optimized
for a specific framebuffer layout.

BR,
Nikolaus

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