On Tue, Jun 13, 2023 at 06:15:12PM +0200, Takashi Iwai wrote:
Mark Brown wrote:
On Tue, Jun 13, 2023 at 04:24:28PM +0200, Takashi Iwai wrote:
Since HD-audio codec has no known default values unlike normal codecs, it needs to initialize itself only at the first access, and this helper does it.
Ah, if it's just suppressing the write the code should just be removed. regmap_update_bits() already suppresses noop writes so unless we might write a different value to the register later the effect will be the same. I can send a patch.
Oh, I'm afraid that we're seeing different things. The code there is rather to *set* some initial value for each amp register (but only once), and it's not about optimization for writing a same value again.
That is, the function helps to set an initial (mute) value on each amp when the driver parses the topology and finds an amp. But if the driver already has parsed this amp beforehand by other paths, it skips the initialization, as the other path may have already unmuted the amp.
Or I might have misunderstood what you mean about _update_bits()...
So it is possible that we might set two distinct values during setup then and we're doing this intentionally? It's not obvious that this might happen. A comment wouldn't hurt, and a big part of this is confusing is that in the non-regmap case all we're doing is suppressing duplicate writes, in that path it's just checking for changes in the register value.
None of this is what the non-regmap path does, it just suppresses noop writes to the hardware.