Re: [PATCH v2] net: phy: disable eee due to errata on various KSZ switches

[Andrew Lunn]

On Mon, Oct 07, 2024 at 10:10:32AM -0700, Tim Harvey wrote:
> The well-known errata regarding EEE not being functional on various KSZ
> switches has been refactored a few times. Recently the refactoring has
> excluded several switches that the errata should also apply to.
> 
> Disable EEE for additional switches with this errata.
> 
> The original workaround for the errata was applied with a register
> write to manually disable the EEE feature in MMD 7:60 which was being
> applied for KSZ9477/KSZ9897/KSZ9567 switch ID's.
> 
> Then came commit ("26dd2974c5b5 net: phy: micrel: Move KSZ9477 errata
> fixes to PHY driver") and commit ("6068e6d7ba50 net: dsa: microchip:
> remove KSZ9477 PHY errata handling") which moved the errata from the
> switch driver to the PHY driver but only for PHY_ID_KSZ9477 (PHY ID)
> however that PHY code was dead code because an entry was never added
> for PHY_ID_KSZ9477 via MODULE_DEVICE_TABLE.
> 
> This was apparently realized much later and commit ("54a4e5c16382 net:
> phy: micrel: add Microchip KSZ 9477 to the device table") added the
> PHY_ID_KSZ9477 to the PHY driver but as the errata was only being
> applied to PHY_ID_KSZ9477 it's not completely clear what switches
> that relates to.
> 
> Later commit ("6149db4997f5 net: phy: micrel: fix KSZ9477 PHY issues
> after suspend/resume") breaks this again for all but KSZ9897 by only
> applying the errata for that PHY ID.
> 
> The most recent time this was affected was with commit ("08c6d8bae48c
> net: phy: Provide Module 4 KSZ9477 errata (DS80000754C)") which
> removes the blatant register write to MMD 7:60 and replaces it by
> setting phydev->eee_broken_modes = -1 so that the generic phy-c45 code
> disables EEE but this is only done for the KSZ9477_CHIP_ID (Switch ID).
> 
> Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> ---
> v2: added fixes tag and history of issue

You did?

Also, you need to set the subject line to net.

https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

       Andrew