<div dir="auto"><div>It could be either, but these names are assigned by the kernel – not by udev.</div><div dir="auto"> <div class="gmail_quote" dir="auto"><div dir="ltr" class="gmail_attr">On Thu, Oct 29, 2020, 22:53 Marcin Kocur <<a href="mailto:marcin2006@gmail.com">marcin2006@gmail.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello, this is the output of turning off and on my display (using power button): [mk@linux ~]$ udevadm monitor monitor will print the received events for: UDEV - the event which udev sends out after rule processing KERNEL - the kernel uevent KERNEL[79.909185] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) KERNEL[79.909318] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3/i2c-dev/i2c-3 (i2c-dev) KERNEL[79.909385] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3 (i2c) KERNEL[79.909564] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-2/drm_dp_aux1 (drm_dp_aux_dev) KERNEL[79.909599] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-2 (drm) KERNEL[79.909733] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3/drm_dp_aux2 (drm_dp_aux_dev) KERNEL[79.909756] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3 (drm) KERNEL[79.909882] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) UDEV [79.912218] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3/i2c-dev/i2c-3 (i2c-dev) UDEV [79.912301] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) UDEV [79.912708] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3 (i2c) UDEV [79.913400] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-2/drm_dp_aux1 (drm_dp_aux_dev) UDEV [79.913832] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3/drm_dp_aux2 (drm_dp_aux_dev) UDEV [79.913875] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-2 (drm) UDEV [79.914230] remove /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3 (drm) UDEV [79.914814] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) KERNEL[85.337964] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3/i2c-dev/i2c-3 (i2c-dev) KERNEL[85.337996] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3 (i2c) UDEV [85.340976] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3/i2c-dev/i2c-3 (i2c-dev) UDEV [85.342384] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/i2c-3 (i2c) KERNEL[85.482056] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3 (drm) KERNEL[85.482116] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3/drm_dp_aux1 (drm_dp_aux_dev) KERNEL[85.482215] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) KERNEL[85.482231] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-4 (drm) KERNEL[85.482308] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-4/drm_dp_aux2 (drm_dp_aux_dev) KERNEL[85.482386] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) KERNEL[85.482415] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) UDEV [85.483698] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3 (drm) UDEV [85.485053] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-3/drm_dp_aux1 (drm_dp_aux_dev) UDEV [85.486553] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) UDEV [85.487973] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-4 (drm) UDEV [85.489186] add /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0/card0-DP-4/drm_dp_aux2 (drm_dp_aux_dev) UDEV [85.490094] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) UDEV [85.491090] change /devices/pci0000:00/0000:00:08.1/0000:08:00.0/drm/card0 (drm) The monitor was visible in xrandr as DP-2, after power off and on it's visible as DP-3 (DP-2 is still there "disconnected"). It's troublesome for: - GUI display configurators - scripting - for Xorg configuration which stops to work: Section "Monitor" Identifier "DP-2" Option "Primary" "true" EndSection Is this a bug or a feature? -- Pozdrawiam / Greetings Marcin Kocur █ _______________________________________________ systemd-devel mailing list <a href="mailto:systemd-devel@lists.freedesktop.org" target="_blank" rel="noreferrer">systemd-devel@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/systemd-devel" rel="noreferrer noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/systemd-devel</a> </blockquote></div></div></div>