Hi, On 16/02/21 2:07 pm, Steen Hegelund wrote: > Hi Andrew and Kishon, > > On Mon, 2021-02-15 at 15:07 +0100, Andrew Lunn wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you >> know the content is safe >> >> On Mon, Feb 15, 2021 at 05:25:10PM +0530, Kishon Vijay Abraham I >> wrote: >>> Okay. Is it going to be some sort of manual negotiation where the >>> Ethernet controller invokes set_speed with different speeds? Or the >>> Ethernet controller will get the speed using some out of band >>> mechanism >>> and invokes set_speed once with the actual speed? >> >> Hi Kishon >> >> There are a few different mechanism possible. >> >> The SFP has an EEPROM which contains lots of parameters. One is the >> maximum baud rate the module supports. PHYLINK will combine this >> information with the MAC capabilities to determine the default speed. >> >> The users can select the mode the MAC works in, e.g. 1000BaseX vs >> 2500BaseX, via ethtool -s. Different modes needs different speeds. >> >> Some copper PHYs will change there host side interface baud rate when >> the media side interface changes mode. 10GBASE-X for 10G copper, >> 5GBase-X for 5G COPPER, 2500Base-X for 2.5G copper, and SGMII for >> old school 10/100/1G Ethernet. >> >> Mainline Linux has no support for it, but some 'vendor crap' will do >> a >> manual negotiation, simply trying different speeds and see if the >> SERDES establishes link. There is nothing standardised for this, as >> far as i know. >> >> Andrew > > Yes, in case I mention the only way to ensure communication is human > intervention to set the speed to the highest common denominator.
Okay.. is it the same case for set_media as well? Thanks Kishon
