[PATCH v2 2/3] ASoC: sunxi: sun4i-spdif: Resume device before kcontrol register access

[Chen-Yu Tsai]

On Sat, May 23, 2026 at 4:55 PM Bui Duc Phuc <phucduc.bui at gmail.com> wrote:
>
> Hi Chen-Yu,
>
> On Sat, May 23, 2026 at 2:19 AM Chen-Yu Tsai <wens at kernel.org> wrote:
> > And when you do add patches due to Sashiko raising an issue, please
> > do mention it in the commit message.
> >
>
> As mentioned in the v1 discussion , this issue was originally reported
> by Sashiko.
> I'll add the Reported-by tag in the next revision.
> v1 links:
> https://lore.kernel.org/all/20260513105003.81880-1-phucduc.bui@gmail.com/
>
> > Did you actually reproduce the issue, or did you add the patch simply
> > because Sashiko mentioned it?
> >
> Since I lack Sunxi hardware, I couldn't reproduce it or perform runtime testing.
> But I did compile-test the patch.
> The patch aims to fix unsafe register accesses that occur before ensuring the
> device is runtime-resumed.

When you submit a patch, it is expected that you already tested it.
If you only compile tested it, please remember to say so in the
footer (or mark the patch as RFT) so that others can test for you
and the maintainer knows the status.

And if possible, provide a scheme to test it.

> > On sunxi, either it will hang the system because the bus transaction
> > got ignored, or it won't as something else enabled the clock.
> >
>
> If Sunxi's PM design already guarantees safe access here,
> feel free to reject the patch.

I can't say that it does. But since the only control that SPDIF gives
is the IEC958 status, and that doesn't appear in the standard mixer apps,
it's unlikely that a _user_ will trigger it. Plus the control was added
after the basic structure of the driver was done, so there is definitely
some possibility of a crash.

But what you wrote in the commit message doesn't match the actual hardware
behavior, like I wrote.


ChenYu