Re: [PATCH v3 05/18] mux: add mux_chip_resume() function

Thomas Richard
2024-02-21T10:59:16Z

On 2/16/24 16:07, Andy Shevchenko wrote:
> On Fri, Feb 16, 2024 at 08:52:17AM +0100, Thomas Richard wrote:
>> On 2/15/24 16:29, Andy Shevchenko wrote:
>>> On Thu, Feb 15, 2024 at 04:17:50PM +0100, Thomas Richard wrote:
>
> ...
>
>>>> +int mux_chip_resume(struct mux_chip *mux_chip)
>>>> +{
>>>> + int global_ret = 0;
>>>> + int ret, i;
>>>> +
>>>> + for (i = 0; i < mux_chip->controllers; ++i) {
>>>> + struct mux_control *mux = &mux_chip->mux[i];
>>>> +
>>>> + if (mux->cached_state == MUX_CACHE_UNKNOWN)
>>>> + continue;
>>>> +
>>>> + ret = mux_control_set(mux, mux->cached_state);
>>>> + if (ret < 0) {
>>>> + dev_err(&mux_chip->dev, "unable to restore state\n");
>>>> + if (!global_ret)
>>>> + global_ret = ret;
>>>
>>> Hmm... This will record the first error and continue.
>>
>> In the v2 we talked about this with Peter Rosin.
>>
>> In fact, in the v1 (mux_chip_resume() didn't exists yet, everything was
>> done in the mmio driver) I had the same behavior: try to restore all
>> muxes and in case of error restore the first one.
>>
>> I don't know what is the right solution. I just restored the behavior I
>> had in v1.
>
> Okay, I believe you know what you are doing, folks. But to me this approach
> sounds at bare minimum "unusual". Because the failures here are not fatal
> and recording the first one may or may not make sense and it's so fragile
> as it completely implementation-dependent.

I guess if there is an error, the resume is completely dead so no need
to continue.
If it's okay for Peter I can return on first failure.

Regards,

--
Thomas Richard, Bootlin
Embedded Linux and Kernel engineering