On Sat, 20.02.10 11:59, Raymond Yau (superquad.vortex2@gmail.com) wrote:
2010/2/19 Lennart Poettering mznyfn@0pointer.de
On Thu, 18.02.10 10:01, Mark Brown (broonie@opensource.wolfsonmicro.com) wrote:
The current logic is to not do any software adjustment if the hardware adjustment is "close enough" to the total adjustment we want to do, tested against a threshold. Which I think is quite a reasonable approach because it enables/disables this feature not globally, but looks at each case and enables this logic only if it really has a benefit.
PA 's watermark is already 20 ms if you want to do any software adjustment by PA server
It's not necessarily 20ms. That's just the default (which we unfortunately had to pick very large, since ALSA right now does not inform us about transfer block granularity).
But anyway, whatever the watermark is: this is a latency we know about, which means that we can delay the hw mixer updating accordingly. But that works correctly only if the hw mixer updating is immediate. WHich it most likely is not.
So we now the software volume adjustment latency. We don't know the hardware volume adjustment latency, and assume it is 0. If we knew both we could sync up both changes perfectly, but this way our model has a weakness.
Lennart