Greetings, On my Dell Inspiron e1705 with a Sigmatel stac9200, there is a "subwoofer" that is attached to a separate speaker pin widget. The "Master" control only controls the 4 main speakers. This patch should enable the subwoofer on similarly equipped laptops, by creating the LFE mixer controls, although at present it is coded to be very specific to the 9200. It assumes that the first mono speaker pin with an amp is the subwoofer, and I assume that no stac9200 implementation in the world has both a Center/LFE line out _and_ an LFE speaker attached. Since the 9200 is only a 2-channel codec to begin with, this seems reasonable, but I've probably made other potentially incorrect assumptions, so please review carefully. One problem with this patch, even if it works as intended, is that it doesn't provide a very satisfying end-user experience, at least for e1705 owners. The problem is that the LFE pin is almost completely independant of the Master control, so to change the volume the user must operate both controls, which will likely throw the audio balance off. This can be avoided by using the PCM control, but PCM has no mute switch. And muting Master does not mute LFE, although setting Master to 0 does mute LFE. So I have another version of this patch that implements the actual LFE channel volume as a function of the master and LFE volumes. It is really, really fugly, but at least it provides nice behavior for the user! It feels wrong to implement that kind of thing in the lowest levels of the driver, but without a plugin mixer API (which I have no clue where to start on that effort!), I don't see any other option. Since the alternative is so fugly, I am holding that back for now, even though it is what I intend to use on my system. But if you are at all interested in it, let me know and I'll clean it up a bit and submit it. I'm not sure whether it was Sigmatel or (more likely) Dell who screwed this up so badly, but somebody should take a beating over this. -Richard
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