PDAs in HAL (Was: Plans for hal 0.5.x)

[David Zeuthen]

On Thu, 2004-12-16 at 20:09 +0300, Andrei Yurkevich wrote:
> Just to sum up the discussion, is this ok for PDAs representation in HAL?:
> 
> 1) Only USB-connected PDAs should appear in HAL device list, not those 
> connected via serial/Ir/Bluetooth;
> 

Right.

> 2) All the PDA-specific properties are merged in the device node of the 
> USB device that represents the PDA in the system, no child device node 
> for PDA should be created
> 

Yep, it would have to be like a two-level thing, like this

 - Computer
  - USB adapter
   - USB device
    - USB interface representing the pda    *
     - serial device                        **
     - serial device                        ***
    - Other USB interface (e.g. audio)
    - Other USB interface (e.g. ethernet)

(see also http://people.redhat.com/dmalcolm/Screenshot-PDA-HAL.png )

We would match the USB interface (marked with *) like this (copied of
Dave Malcoms list)

  <!-- Aceeca MEZ1000 -->
  <device>
    <match key="info.bus" string="usb">
      <match key="usb.vendor_id" int="0x4766">
        <match key="usb.product_id" int="0x0001">
          <merge key="info.category" type="string">pda</merge>
          <append key="info.capabilities" type="string"> pda</merge>
          <merge key="pda.serial.use_net" type="bool">true</merge>
          <merge key="pda.access_method=serial" type="bool">true</merge>
        </match>
      </match>
    </match>
  </device>

(yes, we will change info.capabilities to be of type 'stringlist' when
we get down to that)

OK, so device marked with * now got the capability 'pda' and
applications, like gnome-pilot, can query those. Specifically, some
devices will have pda.access_method=serial. Now, to actually find the
serial device node to use, being ** and ***, we'd need to tag those like
this

  <device>
    <match key="info.category" string="serial">
      <match key="@info.parent:pda.access_method" string="serial">
        <append key="info.category" type="string">pda_endpoint_serial</merge>
        <append key="info.capabilities" type="string"> pda_endpoint_serial</merge>
        <merge key="pda_endpoint_serial.pda_device" type="copy_property">info.parent</merge>
      </match>
    </match>
  </device>

So, that pretty much gives this algorithm for finding PDA's

 1. Find device object of capability 'pda'; this goes into the UI

 2. To actually access the device with UDI=foo (of cap. 'pda') check
    whether you support pda.access_method and do the right thing.

    - E.g. if you support pda.access_method=serial, use hal to search
      for device objects where pda_endpoint_serial=foo (where foo is
      the UID of the 'pda' device object).

    - (for Dave's PDA with two serial interfaces the program would get
       two pda_endpoint_serial device objects back - this problem will
       be left for the application to deal with; if there are any
       properties we can sanely put in hald (e.g. serial.index=0 and
       serial.index=1) to help out here, I'm all for it - I do feel I
       need to understand why there are two serial lines though).

Now, why do I want this two level thing? Because it's important to
associate the fact that the USB interface is an 'pda' and not just the
serial interface. 

How does that sound?

David


_______________________________________________
hal mailing list
hal at lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/hal