On 24.02.2019 16:34, Russell King - ARM Linux admin wrote: > On Sun, Feb 24, 2019 at 04:28:32PM +0100, Heiner Kallweit wrote: >> On 24.02.2019 16:15, Russell King - ARM Linux admin wrote: >>> On Sun, Feb 24, 2019 at 04:04:03PM +0100, Andrew Lunn wrote: >>>>> I think what's not correct is that phydev->autoneg is set >>>>> (by phy_device_create) for a fixed link. >>>> >>>> Fixed-link tries to emulate auto-neg: >>>> >>>> bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE; >>>> >>>> Maybe it needs better emulation of auto-neg? >>> >>> Or maybe it needs to represent a fixed-speed PHY by clearing bit 1.3 >>> (BMSR_ANEGCAPABLE). In any case, 0.12 (BMCR_ANENABLE) is not set, >>> so according to 802.3-2015, we should not be setting 1.5 >>> (BMSR_ANEGCOMPLETE). >>> >>> However, swphy does try to emulate autonegotiation - we do have cases >>> where swphy is used in situations where the speed and duplex are not >>> fixed. It returns an emulated link partner advertisement for the >>> current speed, which would suggest that we should set BMCR_ANENABLE. >>> >> If we emulate auto-neg, then it's not needed to set the speed bits >> in BMCR. Also what just comes to my mind, certain speeds like 1000BaseT >> don't support forced mode. So we may have to go with auto-neg. > > Sure. > >> To avoid the original issue it should be sufficient to copy >> supported -> advertising at a suited place. > Sorry, seems this wasn't clear enough. I don't mean to change swphy but the user side.
> Why bother - the software PHY emulation is an emulation to allow > existing userspace that pre-dates the ethtool API to get some link > parameters. If we augment the PHY emulation in non-standard ways, > userspace will need to be updated to handle those non-standard > ways. If userspace needs to be updated, why not just bite the > bullet and update to ethtool APIs rather than adding more > complication through an emulation layer? > It's not only userspace. Based on my limited knowledge of DSA this code also uses e.g. genphy_read_status() with a fixed link.
