Re: [PATCH net 4/4] net: axienet: Split into MAC and MDIO drivers

[Andrew Lunn]

On Mon, Jun 23, 2025 at 02:48:53PM -0400, Sean Anderson wrote:
> On 6/23/25 14:27, Andrew Lunn wrote:
> > On Mon, Jun 23, 2025 at 11:16:08AM -0400, Sean Anderson wrote:
> >> On 6/21/25 03:33, Andrew Lunn wrote:
> >> > On Thu, Jun 19, 2025 at 04:05:37PM -0400, Sean Anderson wrote:
> >> >> Returning EPROBE_DEFER after probing a bus may result in an infinite
> >> >> probe loop if the EPROBE_DEFER error is never resolved.
> >> > 
> >> > That sounds like a core problem. I also thought there was a time
> >> > limit, how long the system will repeat probes for drivers which defer.
> >> > 
> >> > This seems like the wrong fix to me.
> >> 
> >> I agree. My first attempt to fix this did so by ignoring deferred probes
> >> from child devices, which would prevent "recursive" loops like this one
> >> [1]. But I was informed that failing with EPROBE_DEFER after creating a
> >> bus was not allowed at all, hence this patch.
> > 
> > O.K. So why not change the order so that you know you have all the
> > needed dependencies before registering the MDIO bus?
> > 
> > Quoting your previous email:
> > 
> >> Returning EPROBE_DEFER after probing a bus may result in an infinite
> >> probe loop if the EPROBE_DEFER error is never resolved. For example,
> >> if the PCS is located on another MDIO bus and that MDIO bus is
> >> missing its driver then we will always return EPROBE_DEFER.
> > 
> > Why not get a reference on the PCS device before registering the MDIO
> > bus?
> 
> Because the PCS may be on the MDIO bus. This is probably the most-common
> case.

So you are saying the PCS is physically there, but the driver is
missing because of configuration errors? Then it sounds like a kconfig
issue?

Or are you saying the driver has been built but then removed from
/lib/modules/

	Andrew