Enabling Hotplug

[Alberto Bursi]

On 19/07/22 08:56, Ravi Paluri (QUIC) wrote:
> Hi all,
>      We are trying to enable Hotplug functionality.
> We've our device node under "/dev/<device-node>", which gets created at boot-up.
> SUBSYSTEM of this <device-node> is "subsys". Hence, I created a folder named "subsys" under "/etc/hotplug.d/" and I added a script at this location as per detailed @ https://openwrt.org/docs/guide-user/base-system/hotplug#usagetroubleshooting
> 
> I also modified "/etc/hotplug.json" file with below code but script under "/etc/hotplug.d/subsys" is not getting executed, possibly since we are not getting SUBSYSTEM trigger event?
> 
> ["if",
>           [ "and",
>                   [ "eq", "SUBSYSTEM", "subsys" ],
>                   [ "isdir", "/etc/hotplug.d/subsys" ]
>           ],
>           [ "exec", "/sbin/hotplug-call", "subsys" ]
>   ],
> 
> We've no clue why this trigger event is not getting fired.
> Do we need to enable any kernel configuration flag? (We are using kernel 5.4 version.) or any package needs to selected under openwrt menu etc.
> Any pointers on how to enable hotplug will be very helpful.
> 
> Thanks,
> Ravi
> 
> 
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Hi,

if it is /dev/subsys, then "subsys" is a devname and
I think you need to use

"eq", "DEVNAME", "subsys"

If you have /dev/subsys/item1, /dev/subsys/item2, /dev/subsys/item3 then
"subsys" is a folder and you can use

"isdir", "/dev/subsys"

-Alberto