riscv defconfig CONFIG_PM/macb/generic PHY regression in v5.18-rc1

[Andrew Lunn]

On Tue, Apr 05, 2022 at 02:18:17PM +0000, Conor.Dooley at microchip.com wrote:
> 
> 
> On 05/04/2022 13:25, Andrew Lunn wrote:
> > On Tue, Apr 05, 2022 at 01:05:12PM +0000, Conor.Dooley at microchip.com wrote:
> >> [ 2.818894] macb 20112000.ethernet eth0: PHY [20112000.ethernet-ffffffff:09] driver [Generic PHY] (irq=POLL)
> > 
> > Hi Conor
> > 
> > In general, it is better to use the specific PHY driver for the PHY
> > then rely on the generic PHY driver. I think the Icicle Kit has a
> > VSC8662? So i would suggest you enable the Vitesse PHYs.
> 
> Hi Andrew, thanks for the quick reply.
> It does indeed have a Vitesse VSC8662, but the link never seems to
> come up for me [1] so I have been using Generic PHY. I'll try look
> at why that is. Either way would like to know what's gone wrong in
> the Generic PHY case since that's what's available in the riscv
> defconfig.

Hi Conor

Generic PHY is purely best effort fall back for when there is nothing
better. It might work, it might not, depending on the PHY. If it is a
simple PHY which only implements the registers defined in 802.3 clause
22, and not much more, it has a good chance of working. Otherwise, you
really should be using the specific driver.

Don't worry too much about the defconfig, nobody actually uses
it. Distros have their own which turn on most things. So a real system
probably does have the correct PHY driver.

	 Andrew