Re: [PATCH] USB: serial: cp210x: Fix GPIO in autosuspend
From: Karoly Pados
Date: Tue Jan 15 2019 - 04:18:06 EST
> I think it's better to add the autopm call to gpio210x_gpio_get/set
> only. This will allow for a simpler patch, and keeps the autopm handling
> confined to the gpio paths.
I'll submit a v2.
>> @@ -1383,6 +1397,7 @@ static void cp210x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int
>> value)
>> } else {
>> u16 wIndex = buf.state << 8 | buf.mask;
>>
>> + usb_autopm_get_interface(serial->interface);
>
> Also make sure to always check for errors from autopm_get().
I checked everywhere else, the reason I didn't check here is on purpose based on your previous feedback. The caller function here doesn't have a return value, so the only way to return errors is to log, but in my last patch to ftdi_sio you made clear that errors from autopm_get shouldn't get logged. Trying to call usb_control_msg() even though the device could not wake does not cause issues, and the return value from usb_control_msg() clearly identifies the reason for failure (failure due to autosuspend), so error information is not lost either. So I thought not checking here has no real disadvantage and I still stay conformant to your previous guidance.