On Tue, Mar 18, 2008 at 10:24 AM, ?tienne Bersac <bersace03 at gmail.com> wrote: > Hi, > > In january 2007, happened a very good discussion this list about SANE > and HAL wich led to shipping a basic fdi. > http://lists.alioth.debian.org/pipermail/sane-devel/2007-January/018343.html. > > Currently, sane-desc generate a very basic fdi which only badge device > as scanner and add a property "scanner.access_method" hardcoded to > "proprietary", the latter is pretty useless ;) > > Please keep in mind that supporting HAL does NOT mean depending on HAL > nor breaking API. > > > Abel Deuring did a very nice job on sane-fdi, a parser for .desc file > that provide much useful information right in the fdi. Sadly, the > discussion stopped without a lot of success. I updated the sane-fdi > script from Abel following the advice from Abel and Johannes Meixner. > > A device rule looks like : > > <device> > <match key="usb.vendor_id" int="0x04a9"> > <match key="usb.product_id" int="0x2207"> > <append key="info.capabilities" type="strlist">scanner</append> > <append key="scanner.api" type="strlist">sane</append> > <append key="scanner.sane.model" type="strlist">Canon CanoScan > N1220U</append> > <append key="scanner.sane.backends" type="strlist">plustek</append> > <append key="scanner.sane.backends.plustek.supportstatus" > type="strlist">complete</append> > <append key="scanner.sane.backends.plustek.comment" > type="strlist">Identical to UMAX 3400</append> > </match> > </match> > </device> > > The updated sane-fdi script is available at > http://bersace03.free.fr/pub/Development/Scanner/sane-fdi .
i've not looked at this code yet, but the output above seems reasonable. > There is still one thing needed to get full HAL support by SANE, build > the SANE device name from those infos. > > One goal would be to allow frontend to provide an entry for each backend > allowing user to select the backend to use. Using e.g. "Cannon CanoScan > N1220U (complete support with plustek driver)" along "Canon CanoScan > N1220U (complete support with umax driver)" will allow user to easily > select driver. > > According to discussion about HAL and SANE last year, seems that the > "udi:<backend>:<udi>" would be the solution for SANE to support HAL > (without depending on it). See > http://lists.alioth.debian.org/pipermail/sane-devel/2007-January/018353.html > for details. ok, so lets assume that we have a new 'hal' meta backend to do some 'magic'. when the dll backend is asked to open a device like 'hal:<udi>:<backend>'. it will load the hal backend, and ask it to open '<udi>:<backend>'. the hal backend will load '<backend>', and ask it for a list of scanners it can find, and somehow pick the one that goes with the '<udi>'. i am worried that the last step means that each backend will have to know how to translate udi's. allan -- "The truth is an offense, but not a sin"
