Hi, I'm looking to unload a userspace driver when a particular device is
removed.
My load rule is this:
ACTION=="add",SUBSYSTEM=="usb_endpoint",ATTR{device/manufacturer}=="Crystalfontz",
RUN+="/usr/bin/sv up lcdd"
Now the problem was that when I disconnect the device there is no longer
a "device/manufacturer" file, so I added an environment variable
LCDD_DEVICE to the rule:
ACTION=="add",SUBSYSTEM=="usb_endpoint",ATTR{device/manufacturer}=="Crystalfontz",
ENV{LCDD_DEVICE}="%k", RUN+="/usr/bin/sv up lcdd"
I had hoped to be able to match this LCDD_DEVICE variable when the
kernel name appeared in the remove event. So I tried:
ACTION=="remove", ENV{LCDD_DEVICE}=="%k", RUN+="... remove the driver ..."
But this rule never triggered.
I put in a debug line, and disconnected the device:
ACTION=="remove", RUN+="/bin/sh -c 'logger B %k = $env{LCDD_DEVICE}'"
Jan 1 00:41:21 user.notice root: B usbdev1.23_ep81 =
Jan 1 00:41:21 user.notice root: B usbdev1.23_ep02 =
Jan 1 00:41:21 user.notice root: B usbdev1.23_ep00 = usbdev1.23_ep00
<--- !!!
Jan 1 00:41:21 user.notice root: B ttyUSB1 =
Jan 1 00:41:21 user.notice root: B ttyUSB1 =
Jan 1 00:41:21 user.notice root: B 1-1:1.0 =
Jan 1 00:41:21 user.notice root: B 1-1 =
So there is a situation where %k was equal to LCDD_DEVICE, but
regardless the rule didn't trigger. Did I get the syntax wrong?
Also, it appears that the scope of the environment variable LCDD_DEVICE
only occurs when the actual device has caused the uevent. OK.
So should I make my remove rule like this?
ACTION=="remove", ENV{LCDD_DEVICE}!="", RUN+="... remove the driver ..."
Aras
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