On Wed, 26 Jun 2019 at 10:42, Russell King - ARM Linux admin <li...@armlinux.org.uk> wrote: > > On Wed, Jun 26, 2019 at 02:10:27AM +0300, Vladimir Oltean wrote: > > On Wed, 26 Jun 2019 at 01:58, Russell King - ARM Linux admin > > <li...@armlinux.org.uk> wrote: > > > > > > On Wed, Jun 26, 2019 at 01:14:59AM +0300, Vladimir Oltean wrote: > > > > On Wed, 26 Jun 2019 at 00:53, Russell King - ARM Linux admin > > > > <li...@armlinux.org.uk> wrote: > > > > > > > > > > On Tue, Jun 25, 2019 at 11:24:01PM +0300, Vladimir Oltean wrote: > > > > > > Hi Russell, > > > > > > > > > > > > On 6/24/19 6:39 PM, Russell King - ARM Linux admin wrote: > > > > > > > This should be removed - state->link is not for use in mac_config. > > > > > > > Even in fixed mode, the link can be brought up/down by means of a > > > > > > > gpio, and this should be dealt with via the mac_link_* functions. > > > > > > > > > > > > > > > > > > > What do you mean exactly that state->link is not for use, is that > > > > > > true in > > > > > > general? > > > > > > > > > > Yes. mac_config() should not touch it; it is not always in a defined > > > > > state. For example, if you set modes via ethtool (the > > > > > ethtool_ksettings_set API) then state->link will probably contain > > > > > zero irrespective of the true link state. > > > > > > > > > > > > > Experimentally, state->link is zero at the same time as state->speed > > > > is -1, so just ignoring !state->link made sense. This is not in-band > > > > AN. What is your suggestion? Should I proceed to try and configure the > > > > MAC for SPEED_UNKNOWN? > > > > > > What would you have done with a PHY when the link is down, what speed > > > would you have configured in the phylib adjust_link callback? phylib > > > also sets SPEED_UNKNOWN/DUPLEX_UNKNOWN when the link is down. > > > > > > > With phylib, I'd make the driver ignore the speed and do nothing. > > With phylink, I'd make the core not call mac_config. > > But what happened is I saw phylink call mac_config anyway, said > > 'weird' and proceeded to ignore it as I would have for phylib. > > I'm just not understanding your position - it seems like you're > > implying there's a bug in phylink and the function call with > > MLO_AN_FIXED, state->link=0 and state->speed=-1 should not have taken > > place, which is what I wanted to confirm. > > It is not a bug. It is a request to configure the MAC, and what it's > saying is "we don't know what speed and/or duplex". > > Take for instance when the network adapter is brought up initially. > The link is most likely down, but we should configure the initial MAC > operating parameters (such as the PHY interface). Phylink makes a > mac_config() call with the speed and duplex set to UNKNOWN. > > Using your theory, we shouldn't be making that call. In which case, > MAC drivers aren't going to initially configure their interface > settings. > > _That_ would be a bug. >
So you're saying that: - state->link should not be checked, because it is not guaranteed to be valid - state->speed, state->duplex, state->pause *should* be checked, because it is not guaranteed to be valid Is state->interface always valid? I don't think I follow the pattern here. Or shouldn't I check speed, duplex and pause either, and try to pass the MAC UNKNOWN values, inevitably failing at some point? Do Marvell MACs have an UNKNOWN setting? > > It's unlikely that it would switch between SGMII and USXGMII > > > dynamically, as USXGMII supports speeds from 10G down to 10M. > > > > > > Where interface mode switching tends to be used is with modes such > > > as 10GBASE-R, which doesn't support anything except 10G. In order > > > for the PHY to operate at slower speeds, it has a few options: > > > > > > 1) perform rate adaption. > > > 2) dynamically switch interface type to an interface type that > > > supports the desired speed. > > > 3) just not support slower speeds. > > > > > > > So am I reading this correctly - it kind of makes sense for gigabit > > MAC drivers to not check for the MII interface changing protocol? > > Again, that's incorrect in the general case. Gigabit includes SGMII > and 802.3z PHY protocols which need to be switched between for SFPs. > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up > According to speedtest.net: 11.9Mbps down 500kbps up Thanks, -Vladimir
