On Mon, 14 Sep 2020 13:48:14 +0000 Omer Shpigelman wrote: > On Thu, Sep 10, 2020 at 11:31 PM Jakub Kicinski <k...@kernel.org> wrote: > > On Thu, 10 Sep 2020 23:17:59 +0300 Oded Gabbay wrote: > > > > Doesn't seem like this one shows any more information than can be > > > > queried with ethtool, right? > > > correct, it just displays it in a format that is much more readable > > > > You can cat /sys/class/net/$ifc/carrier if you want 0/1. > > > > > > > nic_mac_loopback > > > > > is to set a port to loopback mode and out of it. It's not really > > > > > configuration but rather a mode change. > > > > > > > > What is this loopback for? Testing? > > > > > > Correct. > > > > Loopback test is commonly implemented via ethtool -t > > This debugfs entry is only to set the port to loopback mode, not running a > loopback test. > Hence IMO adding a private flag is more suitable here and please correct me > if I'm wrong. > But either way, doing that from ethtool instead of debugfs is not a good > practice in our case. > Due to HW limitations, when we switch a port to/from loopback mode, we need > to reset the device. > Since ethtool works on specific interface rather than an entire device, we'll > need to reset the device 10 times in order to switch the entire device to > loopback mode. > Moreover, running this command for one interface affects other interfaces > which is not desirable when using ethtool AFAIK. > Is there any other acceptable debugfs-like mechanism for that?
What's the use for a networking device which only communicates with itself, other than testing?
