udev action only for connecting VGA/HDMI cable but not for disconnecting

Alex Deucher alexdeucher at gmail.com
Fri Aug 19 06:28:29 PDT 2011

On Fri, Aug 19, 2011 at 8:03 AM, Dirk Montgomery <qjn at gmx.de> wrote:
> Hello all,
> I have an AMD Radeon HD 6310 with free radeonhd drivers running. Xorg
> version is 7.6, xserver is 1.10.3.
> I tried to define a udev rule to change my monitor settings autoamtically
> when I connect a VGA or an HDMI cable. Connecting works fine but
> disconnecting is not recognized.
> udevadm monitor shows:
> udevadm monitor
> monitor will print the received events for:
> UDEV - the event which udev sends out after rule processing
> KERNEL - the kernel uevent
> KERNEL[100.176249] change   /devices/pci0000:00/0000:00:01.0/drm/card0 (drm)
> UDEV  [100.869104] change   /devices/pci0000:00/0000:00:01.0/drm/card0 (drm)
> for connecting. For disconnecting nothing happens. Of course with this it is
> not possible to define a rule to change resolution etc. when cable is
> disconnected.
> Is it simply not possible to detect disconntecting of a cable? Or is this a
> bug? Every help related to this is appreciated.

The hw can detect both plug and unplug events.  I'd suggest filing a
radeon drm bug (https://bugs.freedesktop.org) so we can track and
debug this more easily.  Please attach your xorg log and dmesg output
to the bug report.  If you want to see the hw events, you can edit
evergreen_irq_process() in evergreen.c and enable HPD debugging
messages.  They are enabled when you enable drm debugging, but you'll
probably lose them in the general debugging volume so I'd just enable
them alone to make it easier to see the content.  You should get a
message on both plug and unplug events.


> Thank you very much!
> Regards
> Dirk
> --
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