On Fri, Sep 26, 2014 at 2:12 PM, Michael Mrozek EvilDragon@openpandora.org wrote:
Am Thu, 25 Sep 2014 20:16:10 +0300 hat Grazvydas Ignotas notasas@gmail.com geschrieben:
1x for digital BT headset
We have that connected on pandora, but it was never used, there is no driver, we don't even know if hardware works. By default bluez is sending audio via UART data link, so nobody ever complained about missing drivers for the mcBSP link.
The reason not many people use it on the Pandora is simply because it doesn't work properly. I tried it once but didn't get it to work, so that's not a real reason.
It's unlikely we can get it to work on Pyra then for the same reasons it now doesn't work on pandora. The hardware is wasted there, more or less.
I agree that gamers won't do it (latency and bad audio quality), but if someone wants to make a phone call, they will probably use a Bluetooth headset for it.
So while not main priority, it would be nice to use.
That would involve steaming the audio from/to 3G though one link and then from/to BT through other link at the same time. We failed to get single link working on pandora, I don't have much hope we can get 2 of them working simultaneously on Pyra, ALSA + generic Linux software is just not good at such things. It would probably be easier to do on Android, but I don't want to touch that.
...
For latency:
notaz: Could you create a simple tool that will do a small white flash on the screen together with a short beep (100% synchronized) which I can run both on the Pandora and EVM?
You can't 100% synchronize them, Linux is not a realtime OS. It also depends heavily on things like ALSA buffer settings, playback trigger thresholds and driver itself. We could test default driver settings and do multiple experiments to rule out differences caused by OS itself, maybe.
I can then record both with a highspeed camera and test the latency.
For those tests to work we need a proper audio driver (without using a binary blob) for the TWL.
I'll need some instructions how to get that working then, i.e. what to do to get aplay to output sound without binary blob available.