Thank you for review comments.
On Mon, Oct 17, 2016 at 05:38:46AM -0700, Florian Fainelli wrote:
> EXTERNAL EMAIL
> On October 17, 2016 12:31:54 AM PDT, Raju Lakkaraju
> <raju.lakkar...@microsemi.com> wrote:
> >Hi Andrew,
> >Thank you for code review and comments.
> >On Fri, Oct 14, 2016 at 02:12:32PM +0200, Andrew Lunn wrote:
> >> EXTERNAL EMAIL
> >> On Fri, Oct 14, 2016 at 05:10:32PM +0530, Raju Lakkaraju wrote:
> >> > From: Raju Lakkaraju <raju.lakkar...@microsemi.com>
> >> >
> >> > For operation in cabling environments that are incompatible with
> >> > 1000BAST-T, VSC8531 device provides an automatic link speed
> >> > downshift operation. When enabled, the device automatically changes
> >> > its 1000BAST-T auto-negotiation to the next slower speed after
> >> > a configured number of failed attempts at 1000BAST-T.
> >> > This feature is useful in setting up in networks using older cable
> >> > installations that include only pairs A and B, and not pairs C and
> >> Any reason not to just turn this on by default when auto-neg is
> >> enabled?
> >Downshift can enable by default when auto-neg enabled. This is good
> >But we would like to provide option to customer can choose whether this
> >feature need to enable or disable and also configure failure attempts.
> >Do you have any other suggestion how to configure failure attempts?
> Is the speed downshift feature similar to what Intel and Broadcom refer to as
> wirespeed? I have seen cases with Broadcom PHYs where we had to turn such a
> feature on to allow auto-negotiation to complete with 4-wire cables, but this
> had the downside of impacting normal autoneg, so it is left disabled.
Yes. I check the Broadcom wirespeed code. Downshift is similar to wirespeed.
But Broadcom wirespeed configuration in Ethernet controller.
> I would expect the number of customers using this feature to be fairly
> limited, so having a tunable to turn this downshift on/off may be acceptable.
> Ethtool supports a number of tunable parameters now (such as rx_copybreak),
> there may be room for using something similar for boolean flags like these.
This implementation shows little bit specific to Ethernet controller.
Do you have any PHY specific examples?
In another mail thread, you proposed similar to net device features.
Shall i implement that suggestion here?