SpeakUp and the Raspberry Pi...more

[Mike Ray]

Hello,

Forgive me if nobody on here is really interested in this stuff but I 
thought I'd post it on the off-chance it sparks any ideas.

I have identified the reason for the crash of SpeakUp in the Raspberry 
Linux kernel and the mechanism which is responsible.

There is a process running called VCHIQ-0.  This is a user-space 
queueing mechanism which provides an interface to the Broadcom GPU on 
the Pi.  It employs a system whereby user-space applications send it 
messages and they get forwarded to the GPU.  This is done for both PCM 
audio and video.

Until recently the bcm2835 driver did not support MMAP.  It does now but 
there are other problems now with text-to-speech sounding very stuttery.

It occurred to me that with SpeakUp running in kernel-space, and using 
espeakup to connect to espeak in user-space, only for ALSA to then use 
the vchiq mechanism to queue PCM back into kernel-space, would it be 
possible to write a SpeakUp module which totally encapsulates espeak to 
execute in kernel-space?

Mike

-- 
Michael A. Ray
Analyst/Programmer
Witley, Surrey, South-east UK

Interested in accessibility on the Raspberry Pi?
Visit: http://www.raspberryvi.org/

 From where you can join our mailing list for visually-impaired Pi hackers