[yocto] [meta-raspberrypi][PATCH 5/8] Support for vc4 graphics driver: upgrade 4.4 kernel to 4.4.10

[Herve Jourdain]

Hi Andreas,

I've been able to do some testing with the latest 4.1 kernel.
So it can actually "work" in a way, but both the device tree overlay and the driver in the kernel are "old".
This has an impact on stability: I can definitely start wayland/weston, and it's "responsive", BUT after I started playing out with the demo applications, it quickly crashed...
So we could either try to backport the newer driver / dt overlay to the 4.1, which could be possible, or we could just support vc4graphics only for 4.4.10+...

Since 4.1 is not heavily maintained anymore on github, since 4.4 is now the default revision on github, and since development branches for 4.5 and 4.6 are already there on github, I would personally be inclined to support vc4graphics only for 4.4.10+...
And I would also be in favor of moving the default version of the kernel to the 4.4 series...

What do you think is the best option there?

Herve

-----Original Message-----
From: Andreas Müller [mailto:schnitzeltony at googlemail.com] 
Sent: jeudi 19 mai 2016 00:59
To: Herve Jourdain <herve.jourdain at neuf.fr>
Cc: Khem Raj <raj.khem at gmail.com>; Yocto Project <yocto at yoctoproject.org>
Subject: Re: [yocto] [meta-raspberrypi][PATCH 5/8] Support for vc4 graphics driver: upgrade 4.4 kernel to 4.4.10

On Wed, May 18, 2016 at 11:46 PM, Andreas Müller <schnitzeltony at googlemail.com> wrote:
> On Wed, May 18, 2016 at 7:32 PM, Herve Jourdain <herve.jourdain at neuf.fr> wrote:
>> One thing I didn't make configurable, but that maybe could be, is the parameter passed to the overlay.
>> I selected cma-256, based on experience from other people, and because my configuration is RPI2/3 with 1G of memory.
>> I realize it might not work well with RPI0/1, which have less memory available...
>> So even if I believe cma-256 is a good default value, it might be made selectable by the user, if we want to consider vc4 on RPI0/1.
> I played around with vc4 to but did not manage to get it work for an 
> elder version 4.1 of kernel.
what I meant: did only work for elder 4.1 - not current 4.1
>
> I did in rpi-config:
>
> CMA_SIZE = "cma-256"
> CMA_SIZE_raspberrypi = "cma-64"
> CMA_SIZE_raspberrypi0 = "cma-128"
> ...
> echo "dtoverlay=vc4-kms-v3d-overlay,${CMA_SIZE}"
>>>${DEPLOYDIR}/bcm2835-bootfiles/config.txt
>
> This is nothing but an untested suggestion.
>
> Without testing your series I would be very happy to see this or very 
> similar applied in master: Since vc4 works, RaspberryPi turned into my 
> reference test board - e.g. have not seen kde5 running that nice on 
> another board..
>
> Andreas