Re: [PATCH net-next] net: dsa: felix: suppress -EPROBE_DEFER errors

From: Michael Walle
Date: Thu Apr 07 2022 - 10:04:29 EST

Am 2022-04-07 15:56, schrieb Vladimir Oltean:
On Thu, Apr 07, 2022 at 03:06:25PM +0200, Michael Walle wrote:
Due to missing prerequisites the probe of the felix switch might be
[ 4.435305] mscc_felix 0000:00:00.5: Failed to register DSA switch: -517

It's not an error. Use dev_err_probe() to demote the error to a debug
message. While at it, replace all the dev_err()'s in the probe with

Signed-off-by: Michael Walle <michael@xxxxxxxx>

Please limit the dev_err_probe() to dsa_register_switch(). The resource
that is missing is the DSA master, see of_find_net_device_by_node().
The others cannot possibly return -EPROBE_DEFER.

This was my rationale (from the function doc):

* Note that it is deemed acceptable to use this function for error
* prints during probe even if the @err is known to never be -EPROBE_DEFER.
* The benefit compared to a normal dev_err() is the standardized format
* of the error code and the fact that the error code is returned.

In any case I don't have a strong opinion.

Should this be a patch with a Fixes tag?

Whichever way you wish, no preference.

I'll limit it to just the one dev_err() and add a Fixes,
there might be scripts out there who greps dmesg for errors.