[Letux-kernel] TILER patches for Pyra

[H. Nikolaus Schaller]

Hi all,

> Am 08.12.2018 um 15:57 schrieb aTc <atc at k-n-p.org>:
> 
> On 12/8/18 1:33 PM, H. Nikolaus Schaller wrote:
>> Hi,
>> I have seen that ED has announced that there is a new set of TILER patches:
>> 	https://pyra-handheld.com/boards/threads/wrapping-everything-up.83465/
>> "zmatt has reimplemented his rotation hack (so the Pyra is finally fully usable again!)"
>> Is this reimplementaion available anywhere for integration into the letux tree?
> 
> https://github.com/mvduin/linux/commits/letux-4.19.3/hack

> 
> I applied it to the 4.19.4 kernel, 4.19.3 is very unstable.
> 
> It's a quick hack though, not the cleaned up version zmatt mentioned here before.

I have looked through them and they work if applied.
But one patch breaks on other platforms (omap3).

I remember that we had already discussed that and I found that

http://git.goldelico.com/?p=letux-kernel.git;a=commit;h=4f7cefb1416dca96d2a48d5cf884b01c010d4992

tries to fix it. But makes it a platform dependent compile.

So we had discussed that a while ago, worked on a solution and
then forgot about it because it worked with X11 on all platforms.

Therefore I'd suggest a better fix is to detect OMAP5 in

drivers/video/fbdev/core/fbmem.c

and make the #if dynamic.

I remember there was some API to check for the exact platform.
Something where patterns could be provided and it was used
to decide between AM/DM37xx and AM33xx. Maybe in the PVR/SGX
driver stuff?

So something like

if (platform_is("OMAP543[02]"))
	vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
else  // all others incl. OMAP3 w/o TILER
        fb_pgprotect(file, vma, start);

could be the better hack...

Does anyone remember how this "platform_is" function is called?

BR,
Nikolaus