On Tue, Apr 13, 2021 at 12:00:45PM +0200, Lucas Stach wrote: > I agree with the opinion that those PHY fixups introduce more harm than > good. Essentially they are pushing board specific configuration values > into the PHY, without any checks that the fixup is even running on the > specific board it was targeted at.
Yes and no. The problem is, that's an easy statement to make when one doesn't understand what they're all doing. Some are "board specific" in that the normal setup for e.g. iMX6 would be to enable clock output from the AR8035 PHY and feed that into the iMX6 - as far as I'm aware, that's the only working configuration for that SoC and PHY. However, it's also true that this fixup should not be applied unconditionally. Then there's SmartEEE - it has been found that the PHY defaults for this lead to link drops independent of the board and SoC that it is connected to. It seems that the PHY is essentially broken - it powers up with SmartEEE enabled, and when connected to another SmartEEE supporting device, it seems guaranteed that it will result in link drops in its default configuration. Freescale's approach has apparently been to unconditionally disable SmartEEE for all their platforms because of this. With a bit of research however (as has been done by Jon and myself) we've found that increasing the Tw parameter for 1G connections results in a much more stable link. So, just saying that these are bad without actually understanding what they are doing is _also_ bad. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
