On Wed, Jun 17, 2020 at 09:24:50PM +0100, Russell King - ARM Linux admin wrote:
> On Wed, Jun 17, 2020 at 08:43:34PM +0200, Andrew Lunn wrote:
> > You have explained what the change does. But not why it is
> > needed. What exactly is happening. To me, the key thing is
> > understanding why we get -110, and why it is not an actual error we
> > should be reporting as an error. That is what needs explaining.
>
> The patch author really ought to be explaining this... but let me
> have a go. It's worth pointing out that the comments in the file
> aren't good English either, so don't really describe what is going
> on.
>
> When this PHY is in EDPD mode, it doesn't always detect a connected
> cable. The workaround for it involves, when the link is down, and
> at each read_status() call:
>
> - disable EDPD mode, forcing the PHY out of low-power mode
> - waiting 640ms to see if we have any energy detected from the media
> - re-enable entry to EDPD mode
>
> This is presumably enough to allow the PHY to notice that a cable is
> connected, and resume normal operations to negotiate with the partner.
>
> The problem is that when no media is detected, the 640ms wait times
> out (as it should, we don't want to wait forever) and the kernel
> prints a warning.
Hi Russell
Yes, that is what i was thinking.
There probably should be a comment added just to prevent somebody
swapping it back to phy_read_poll_timeout(). It is not clear that
-ETIMEOUT is expected under some conditions.
Andrew
