Re: [PATCH net-next 4/7] net: phy: marvell10g: Add support for 2.5GBASET and 5GBASET

Hello Andrew, Russell,

On Mon, 21 Jan 2019 21:17:15 +0100
Andrew Lunn [off-list ref] wrote:

quoted

@@ -264,8 +265,10 @@ static int mv3310_config_init(struct phy_device *phydev)
 	if (ret)
 		return ret;
 
-	linkmode_and(phydev->advertising, phydev->advertising,
-		     phydev->supported);
+	/* Make sure we advertise all the supported modes, and not just the
+	 * default one specified in the driver's .features.
+	 */
+	linkmode_copy(phydev->advertising, phydev->supported);  

So by doing a copy of supported into advertising, you can stomping
over any restrictions applied via of_set_phy_supported(),
of_set_phy_eee_broken(phydev), and any pause control settings which
might of happened.

Thanks for the explanations, this is indeed clearly not a good solution.

What might make sense here is that a PHY driver can replace its
.features member at run time, in its config_init() call. The core then
needs to perform these evaluations. So i'm guessing we need to split
this code out of probe() and move it into phy_init_hw()?

So the .features won't be read-only anymore ? We could also simply make
a helper that would add a mode to both the supported and advertising
modes list, that would be used in the 'genphy_c45_pma_read_abilities'
and config_init ?

I lack the big picture of the PHY init sequence, there seems to be a
lot of quirks and complex cases that we need to take into account, so
I'll let you decide :)

Heiner, you know this code better than anybody. What do you think?

Andrew

Thanks for the feedback,

Maxime

-- 
Maxime Chevallier, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com