Re: [RFC/PATCH] input_id: add touchpad quirks rules file.

[Martin Pitt <martin.pitt@ubuntu.com>]

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Hello Peter,

Peter Hutterer [2010-05-13 14:03 +1000]:
> I kind-of expect some more tags like this to appear in the future, so I
> figured the generic name touchpad-quirks is better than have a dell-specific
> one. Would something like this be appreciated in the upstream repo?

There's one more dimension to that, where those rules should be
maintained: We can ship them in udev proper (as your patch proposes),
or ship the udev rules in the package which will actually make use of
it, like xorg-input-synaptics (which is what Debian/Ubuntu are
currently doing).

My preference is that we should keep subsystem specific rules in the
subsystem daemon/libraries (like udisks/upower/X.org/libgphoto2)
instead of centrally managing them in udev, for three reasons:

 (1) The subsystem daemon maintainers are usually the experts, and know
     better how that particular hardware should be configured.
 
 (2) I hear that udevd will eventually go away, and its probers will
     be fanned out to the subsystem daemons, therefore leaving the
     udev package as a relatively stable library only.
 
 (3) udev rules and xorg.conf.d/ snippets would be maintained at the
     same place and can be updated in lockstep, instead of creating a
     tight dependency relation.

(3) particularly addresses your remark about the current distro
inconsistency between tag names.

If you do not want to maintain those rules in the synaptics package
for some reason, I would not object to committing them into udev, but
I think we are a lot less flexible that way.

> Looking at the Ubuntu sources for the synaptics driver, the choice there is
> to simply tag with the model name (e.g. "inspiron_1011") and then have the
> xorg.conf hook onto this.

This was by and large arbitrary, since it wasn't clear whether
different models would need different AreaBottomEdge values.

For the record, we also have two more quirks [1], which seem quite model
specific.

> There's two sides to it, the Ubuntu approach is more flexible if other
> configuration options are needed too, the approach here only requires
> updating udev for new models but not Xorg.

I agree that it's nicer to use more generic tag names where
appropriate, i. e. where more models are affected. Coordinating tag
addition, splitting, and merging would also be much easier if they
would be maintained at the same place, and shipped in the same tarball
release, etc.

Thank you, and have a great day,

Martin


[1]
ATTR{[dmi/id]product_name}=="Inspiron 1120", ENV{ID_INPUT.tags}="inspiron_1120"
ATTR{[dmi/id]product_name}=="HP MiniNote 1000", ENV{ID_INPUT.tags}="mininote_1000"

Section "InputClass"
        Identifier "Dell Inspiron quirks"
        MatchTag "inspiron_1120"
        MatchDevicePath "/dev/input/event*"
        Driver "synaptics"
        Option "JumpyCursorThreshold" "250"
EndSection

Section "InputClass"
        Identifier "HP Mininote quirks"
        MatchTag "mininote_1000"
        MatchDevicePath "/dev/input/event*"
        Driver "synaptics"
        Option "JumpyCursorThreshold" "20"
EndSection


-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)

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