Weston on framebuffer?

[Christer Weinigel]

Hi,

I'm trying to port Linux to a Samsung S3C2416 based system (actually an
oscilloscope, http://blog.weinigel.se/2016/05/01/sds7102-hacking.html).

The S3C2416 is a 400MHz ARM9 with a fairly dumb framebuffer, it has some
2D acceleration (pixel/line drawing with alpha, copy rectangle with
alpha and/or color key) but as far as I can tell nobody has added Linux
support for it.

I'm going to need some kind of GUI for the box and somebody mentioned
that Weston has framebuffer support nowdays.  I turned on the Weston
config option in buildroot (2015.5) and managed to get something that
didn't work to begin with, the OS abstraction stuff requires support for
posix_fadvise but for some reason that didn't work with ulibc but I
hacked around that.  libinput didn't like eudev and didn't want to
recognize a USB keyboard and USB mouse to begin with but I just
hardcoded the device type instead of relying on udev to tag the devices.

With this I managed to get a desktop and was unable to start
wayland-terminal.  Redrawing of the graphics felt fairly snappy, but the
lag from pressing a key on the keyboard until a character showed up in
the terminal was slow, probably between a quarter to half a second.

So my question is if this is the performance I should expect with weston
on a 400MHz ARM9 and a dumb framebuffer?  Have I done something stupid
and there are easy ways to speed it up?

Is there any documentation on how to convert the framebuffer driver for
the S3C2416 to a KMS driver and how to add acceleration support?  Can
weston use this?

Or is wayland/weston not really suited for this kind of old hardware and
what should I use in that case?

  /Christer