[maemo-developers] DSP framebuffer access on N8x0

[From: Simon Pickering]

Hi all,

Just a quick heads up to say that it is now possible to access the
framebuffer from the DSP on the N8x0 devices in the same way as is possible
on the 770.

This requires two things, a kernel patch, and adding a FRAMEBUFFER section
to the /lib/dsp/avs_kernelcfg.cmd file. See
https://bugs.maemo.org/show_bug.cgi?id=3123 for the patch.

Note that adding the FRAMEBUFFER section to this file means that the DSP
cannot be restarted (as it will read in this file and automatically attempt
to share the framebuffer again, which crashes the ARM-side dynamic loader
daemon (dsp_dld) which then causes a reboot).

This may or may not be an issue, and can probably be solved by either
getting dsp_dld to not crash if the framebuffer mapping fails (and just
assume that it's already been mapped) or by adding another kernel tweak so
that it checks to see if the framebuffer is already shared and doesn't
return an error if the ioctl is called more than once.

Anyway, onwards with the DSP image processing/video scaling/whatever your
heart desires! :)

Cheers,


Simon