On Mon, 1 Feb 2021 10:14:35 -0800 Edwin Peer wrote: > On Mon, Feb 1, 2021 at 5:49 AM Danielle Ratson <daniel...@nvidia.com> wrote: > > Ok, ill send another version with the symmetrical side. Ethtool > > will try to compose a supported link_mode from the parameters from > > user space and will choose randomly between the supported ones. > > Sounds ok? > > I think it should be deterministic. It should be possible to select > the appropriate mode either based on the current media type or the > current link mode (which implies a media type). Alternatively, if the > user space request only specifies a subset, such as speed, fall back > to the existing behaviour and don't supply the request to the driver > in the form of a compound link mode in those cases (perhaps indicating > this by not setting the capability bit). The former approach has the > potential to tidy up drivers if we decide that drivers providing the > capability can ignore the other fields and rely solely on link mode, > the latter is no worse than what we have today.
The media part is beginning to sound concerning. Every time we under-specify an interface we end up with #vendors different interpretations. And since HW is programmed by FW in most high speed devices we can't even review the right thing is done. At least it's clear what setting a number of lanes means.
