[systemd-devel] systemd unit review requested

["Jóhann B. Guðmundsson"]

On 12/05/2013 12:28 PM, Michael Biebl wrote:
> 2013/12/5 "Jóhann B. Guðmundsson"<johannbg at gmail.com>:
>> On 12/05/2013 06:50 AM, Peter Hutterer wrote:
>>> ExecStartPre=/usr/sbin/modprobe wacom_w8001
>> Add a configuration file called wacom-w8001.conf to /etc/modules-load.d
>> directory with the following content to load the module
>> ( /etc/modules-load.d/wacom-w8001.conf )
>> # Load wacom_w8001 at boot
>> wacom_w8001
> Well, this loads the kernel module unconditionally, though. Even for
> users which don't have that hardware. So this approach isn't that
> great.
>
> It also depends on the wacom_w8001 and how it reacts when it's loaded
> and no hardware is present.
>
> Peter, couldn't this module be autoloaded?

I'm not that familiar with udev policy regarding rules rule but I would 
think that if you autoload module you tie the startup of the systemd 
unit to the module being loaded ( if the intent is to trigger a unit )

So we need an udev wacom-serial-driver rule that might look like this 
for the wacom serial devices

ACTION=="remove", GOTO="drivers_end"
ENV{MODALIAS}=="?*", RUN{builtin}="kmod load $env{MODALIAS}"
SUBSYSTEM=="tty|pnp", SUBSYSTEMS=="pnp", ATTRS{id}=="WACf*", 
ENV{ID_MODEL}="Serial Wacom Tablet $attr{id}", ENV{ID_INPUT}="1", 
ENV{ID_INPUT_TABLET}="1", ENV{NAME}="Serial Wacom Tablet $attr{id} 
,RUN{builtin}="kmod load wacom_w8001"
SUBSYSTEM=="tty|pnp", SUBSYSTEMS=="pnp", ATTRS{id}=="FUJ*", 
ENV{ID_MODEL}="Serial Wacom Tablet $attr{id}", ENV{ID_INPUT}="1", 
ENV{ID_INPUT_TABLET}="1", ENV{NAME}="Serial Wacom Tablet $attr{id} 
,RUN{builtin}="kmod load wacom_w8001"
LABEL="drivers_end"

Followed by an systemd rule that looks something like this

SUBSYSTEM=="module", KERNEL=="wacom*", TAG+="systemd", 
ENV{SYSTEMD_WANTS}+="wacom-inputattach@%k.service"

And the modprobe would be dropped from that unit file but as I say I'm 
not all that familiar with udev policy rules and I personally had not 
planned on mastering udev until I started the cleanup process in Fedora 
which might never happen today thanks to the that WG process.

JBG