[PATCH] phy: Fix generic_setup_phy return value on power on failure

[Marek Vasut]

On 7/12/23 09:36, Jonas Karlman wrote:
> On 2023-07-12 03:48, Marek Vasut wrote:
>> On 7/12/23 02:06, Jonas Karlman wrote:
>>> On 2023-07-12 01:59, Marek Vasut wrote:
>>>> On 7/12/23 01:48, Jonas Karlman wrote:
>>>>> generic_setup_phy may mask a power on failure due to the return value
>>>>> from generic_phy_exit, typically 0, is being used as return value.
>>>>>
>>>>> Fix this by ignoring the return value of the generic_phy_exit call,
>>>>> also remove an unnecessary check for -ENOENT.
>>>>
>>>> Why is it unnecessary ?
>>>> If I recall it right, the ENOENT check is to not fail if the PHY is not
>>>> present in DT, which may not be a failure.
>>>
>>> In the current state ret is returned any way, so this check is currently
>>> pointless.
>>
>> I don't think so, the test is:
>>
>> if (ret && ret != -ENOENT)
>>     return ret;
>>
>> i.e. the ENOENT is a special case.
> 
> Sure, but in this function such check does not affect any outcome.
> The function look like:
> 
>    if (ret) {
>        if (ret != -ENOENT)
>            return ret;
>    } else {
> 	  // init and power on
>    }
>    return ret;
> 
> As seen above ret is always returned unless it is 0 in the initial check,
> making the ENOENT check unnecessary and misleading in this function.

Ah, I see it now, thanks for clarification.

> The old ehci_setup_phy function, see [1], returned 0 instead of ret as
> the final return statement, making the ENOENT check meaningful.
> 
> This change in behavior may have been unintentional in [2]. Because this
> new behavior was merged in v2023.01-rc1, I did not see it appropriate to
> revert back to the old ehci_setup_phy behavior and instead just removed
> the unnecessary ENOENT check.

I somehow suspect that if you get ENOENT, you might need to return 0, 
but please wait for Patrice to double-check.

> I can include a check for ENOENT at the generic_setup_phy call sites if
> we want to restore the old behavior?

Probably no due to duplication. But please wait for Patrice.