We have been trying qt 4.8 for linux arm system, and just recently grabbed the 4.8.4 release.
There had been an annoying problem with spamming about QWS Lock/Unlock messages which we hoped was fixed.

I found this post which has a patch, and that did the trick.

http://www.mail-archive.com/communit.../msg65512.html

The suggested patch seems reasonable, though wondering how come it hasn't been merged in yet.

Using open-source version, and particularly interested in qmultimedia / phonon / gstreamer stack.
Any performance tuning tips would be appreciated.

--DaveM