[PATCH] fbdev: Add an fbdev compositor backend using pixman and evdev

[David Herrmann]

Hi

On Sat, Jan 19, 2013 at 7:12 PM, nerdopolis
<bluescreen_avenger at verizon.net> wrote:
> Hi.
>
>
>
> I tried experimenting with the latest fbdev-backend on my Live CD on an old
> Intel laptop and it seems to work pretty good.
>
>
>
> However I did run into a few problems with VirtualBox which isn't really the
> fault of fbdev-backend, but problems that prevented it from working.
>
>
>
> I tried to use Weston with fbdev on a test build of my Live CD on Virtual
> Box:
>
> It seems that either something in the Casper scripts, or udev prevents
> /dev/fb0 from being created when starting as a live CD.
>
> however once I install and boot the same system, I have a /dev/fb0, which
> allows me to use the fbdev-backend under VirtualBox. Frome here I have to
> pass a VGA= option to the installed kernel with GRUB, or get a weston
> session with the size of 640x480.
>
>
>
> (I found that some applications that use the framebuffer (such as fbterm)
> try to fall back to using VESA, but it seems it requires root access I
> think, so I don't know if this is possible for Weston.)

I don't think this is a good idea. We have a vesafb in the kernel so
please use this instead of accessing graphic-cards via VESA from
user-space.
I don't see any reason why we should copy vesafb-code into weston.

vesafb provides a fbdev device which then can be used by weston.

> So it seems that even on cards that support the framebuffer, a framebuffer
> device is not always created. Would this probably end up being a job for the
> weston-launch helper to possibly use udev to create /dev/fb0, (and maybe
> even change the size)?

In my opinion this is a misconfigured system. udev is used on most
linux systems to set up nodes in /dev. If udev is not used or if it
fails, you should fix your system not weston.
I cannot see any reason why we should work around udev/system bugs in
weston. But that does not mean you cannot convince us ;)

Regards
David