On Tue, Apr 23, 2019 at 09:34:08AM -0600, Alex Williamson wrote: > On Tue, 23 Apr 2019 09:33:53 -0500 Alex G <mr.nuke.me@xxxxxxxxx> wrote: > > 0.5W savings on a 100+W GPU? I agree it's meaningless. > > Evidence? Regardless, I don't have control of the driver that's making > these changes, but the claim seems unfounded and irrelevant. On laptops, 0.5 W can result in noticeably longer battery life. > I can see why we might want to > be notified of degraded links due to signal issues, but what I'm > reporting is that there are also entirely normal and benign reasons > that a link might be reduced, we can't seem to tell the difference > between a fault and this normal dynamic scaling, and the assumption of > a fault is spamming dmesg. So, I don't think what we have here is well > cooked. Do drivers have a mechanism to opt-out of this error > reporting? Is dmesg spammed even if no driver is bound to a GPU? If so, that would suggest a solution that's not dependent on drivers. E.g., the bw_notification port service could avoid reports for devices matching PCI_BASE_CLASS_DISPLAY. (It could also avoid binding to ports whose children include such a device, but the child may be hot-pluggable and thus appear only after the port is bound.) Then we'd still get a notification on boot about degraded link speed, but not continuous messages. Thanks, Lukas
