On Wed, Feb 23, 2022 at 03:55:54PM +0100, Takashi Iwai wrote:
But, more reading the code, I suspect whether the function does work correctly at all... How is the mask calculation done in that way? unsigned int mask = (1U << (fls(min + max) - 1)) - 1; What's the difference of this function with snd_soc_put_volsw()?
Yeah, I'm not clear either - Marek mentioned _SX when he was doing the patch but I didn't get the bandwidth to figure out what it's doing properly yet. At this point I'm not clear what _SX is supposed to do, I'm hoping it works well for the devices that use it but I don't have any of them.
Furthermore, the mask calculation and usage in snd_soc_put_volsw() isn't right, either, I'm afraid; if the range is [-10, 0], max=0, then mask will 0, which will omit all values...
Indeed, if anyone did that. Fortunately I don't *think* that's an issue. The whole way that code handles signed bitfields by remapping them into unsigned user visible controls is a landmine, it's not even obvious that they handle signed bitfields in the first place.