On Mon, Jul 09, 2007 at 03:09:34PM -0700, [EMAIL PROTECTED] wrote: > Both of your suggestions in the OS level help linuxwacom users, that > is for sure. My concern is how do we deal with a system with 2 > identical tablets. I know users running 2 Cintiq 21 UX to gain full > accuracy and flexibility. Right now, the system has trouble to tell > which Cintiq is the first monitor when the system wakes up from a > sleep or even a nap :). Do you guys have any suggestion?
I thought we'd got stuck without a good answer to this previously. The full thread is at: http://sourceforge.net/mailarchive/message.php?msg_name=20060418020303.GA16999%40hank.shelbyville.oz But the main bits of note to this question were me wondering: if there is a serial number or other unique id in the tablet that we can access, then we can always make a <TabletType>-<SerialNum> link or similar that people could use. To which you confirmed: As a short reply to the following discussion, there is no tablet specific id to distinguish tablets of the same model and size. So at this stage, the only method I'm aware of that we could use to distinguish two identical devices reliably would be to use the /dev/input/by-path links to differentiate them by the usb port they are plugged into (since that's really the only thing the machine can know about them that is different but potentially stable). They aren't the most user friendly invention in the world, and will need to be configured for each individual user, but for a static workstation where the tablets are plugged in once and left that way, they should always give the same unique device name for each tablet. Its just a bit brittle if you start moving things about and has a small initial hand-hack burden. But I guess if we can't convince the hardware crew to add a unique identifier of some sort to new tablets (and even if we could, that doesn't help anyone today), then we'll just need to make the by-path configuration more friendly to users somehow... hmm. We should be able to concoct a reasonable by-path rule specific to wacom devices that auto-configuration tools can fairly easily pattern match, but which will remain the same until the device is moved to a different port... It will probably depend on a relatively recent udev, but starting from the set of rules I posted earlier, try something like: ----- psuedo patch ---- # Convenience link for the common case of a single tablet. KERNEL=="event[0-9]*", SYSFS{idVendor}=="056a", SYMLINK="input/wacom" + # You probably won't need this IMPORT rule, since an earlier file is + # likely to have already done it, but the rule that follows it does + # depend on that having happened to set ID_PATH. + # IMPORT{program}="path_id %p" + + # Port specific link for users of multiple tablets of the same type. + KERNEL=="event[0-9]*", SYSFS{idVendor}=="056a", ENV{ID_PATH}=="?*", SYMLINK+="input/by-path/$env{ID_PATH}-wacom" # Type-named links for multiple tablets. If you want to use multiple ----------------------- Here this gives me (for one tablet): /dev/input/by-path/pci-0000:00:02.0-usb-0:4:1.0-wacom -> ../event4 /dev/input/by-path/pci-0000:00:02.1-usb-0:4:1.0-wacom -> ../event4 ... when I plug it into two different usb ports. Should work much the same if you try it with two tablets. If nobody here can get it to wreck their system then I can include something like it for the next upload. It's not a great answer, but it adds a constant factor to the device name that should survive a simple suspend or reboot reliably enough, and lets people search for *-wacom instead of having to figure out which *-event devices they want from that lot -- which is a bit more friendly than having the entire name be like black magic to them... If anyone can think of a better way to do this I'd love to hear it. Cheers, Ron ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Linuxwacom-discuss mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linuxwacom-discuss
