On 2/23/22 17:32, Mark Brown wrote:
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.
Right, I wasn't sure about the remaining two -- volsw_sx and xr_sx --
that's why I only did this one I could at least test.
But CS42L51 is on STM32MP1 DKx devkit, CCing Alex , ST might be able to
look at that one and test.
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.
[...]
