[Letux-kernel] Lay common foundation to make PVR/SGX work without hacks on OMAP34xx, OMAP36xx, AM335x and potentially OMAP4, OMAP5

[H. Nikolaus Schaller]

Hi,

> Am 15.02.2019 um 13:52 schrieb Merlijn Wajer <merlijn at wizzup.org>:
> 
> Hi,
> 
> On 15/02/2019 13:43, H. Nikolaus Schaller wrote:
>> 
>> IMHO this is the first example where this collaboration of our group is already very helpful because
>> we start to exchange knowledge about common problems.
> 
> Yay!
> 
>> 
>> For this patch, the key question is what a better solution will be. Most likely reworking the
>> "pgoff << PAGE_SHIFT" stuff from which I remember that it is used quite a lot. But that should be
>> done once for all and everybody on our future master branch.
>> 
>> So I now have back an (almost) working reference system on v5.0-rc6 for GTA04, BeagleBoard,
>> BeagleBone, PocketBeagle and potentially OpenPanodra (which uses the omap3430/sgx121 variant).
> 
> And the OpenPandora is similar to the Nokia N900 (sgx121). If you have
> the userspace sgx driver that still supports X, you might be able to get
> accelerated 3D on X if you use the maemo leste ddx and userspace driver.
> 
> https://github.com/maemo-leste/n9xx-ti-omap3-sgx
> https://github.com/maemo-leste/n9xx-xf86-video-fbdev-sgx
> 
> (armhf known to work on n900, armel not)
> 
> I don't know how well older userspace works with the latest kernel
> interface, though.

Yes, there are subtle dependencies.

> 
>> At least I can download and start firmware. I just have to find a way to fix the omaplfb so that it works
>> with our omapdrm based panels to runs the CLipBlit test [1] on modern kernels...
> 
> Maybe you can compare with what we have here:
> https://github.com/maemo-leste/n9xx-linux/tree/pvr-wip-4.15.7/drivers/gpu/pvr

I'll take a look into it especially how omaplfb is done.

First observation is that there is a "flat" tree while I am working on a structured one...
But that is just a marginal difference (mainly significant for Makefile writers).

BR and thanks,
Nikolaus