Does the player remember what level it set the volume at, or does it read it back from the kernel/DSP?

Not 100% sure. The ioctls allow the volume to be read. I *believe* that the player sets the volume, and then reads it back for the display, and I know that the player remembers the volume when shutting down so that it boots at the same level next time. But I don't believe that the player particularly cares about what the volume is otherwise.


If you try and change it through the player, it'll bring up the volume display, which would cause problems. (Or... There's a serial command to change the volume. Does it bring up the volume display?)


No if I understand you correctly, you're missing the point. GPSapp would use the same ioctls that exist in the *kernel* that the player uses, not use the player itself to make the changes.