#51 Usable Multitouch Support

Beta
closed-fixed
5
2008-08-23
2007-11-20
No

This patch fixes a bunch of multitouch issues:

1) CVS wasn't properly dropping pressure events generated by the stylus.

2) Tapping the screen now clicks the mouse instead of dragging it.

3) I hacked in some auto calibration code. Touch the top left and bottom right corners to calibrate. I needed this because my system's calibration doesn't match the hardcoded values in the source.

4) Multitouch is now compatible with screen rotation.

5) My touchpad sends spurious negative and zero readings during dragging. This randomly clicks on the gnome start menu, and breaks auto calibration. This patch attempts to filter them out.

Discussion

  • Russell Sears

    Russell Sears - 2007-11-20

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    Oops; the eraser was broken in the last version of the patch. This should fix it.
    File Added: linuxwacom-multitouch-fix-stylus-drag-rotate-and-calibration-v2.patch

     
  • Danny Al-Gaaf

    Danny Al-Gaaf - 2007-11-23

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    Could you please add a diff with -Nur, it's much easier to read!

     
  • Russell Sears

    Russell Sears - 2007-11-23

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    Sorry about that; I must have forgotten the -u (the new files mentioned by the diff are all just autogenerated crud...).

    I've uploaded a new version, with one more fix. After using it for a few days, I realized that the touch screen should be disabled whenever the pen is sending proximity events. Otherwise, it's difficult to write (you can't rest your hand on the screen...), and it occasionally sends spurious left clicks when you use the eraser.

    File Added: linuxwacom-multitouch-fix-stylus-drag-rotate-and-calibration-v3.patch

     
  • Russell Sears

    Russell Sears - 2007-11-23

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    I looked at that patch before writing this one.

    I think my patch supersedes that one, in that it fixes the eraser and the stylus. However, mine makes use of more static variables to track state. The driver really should treat the multitouch data separately from the stylus data (so that events from the two devices don't change each other's state). Then it would be easy to use the stylus state to filter spurious multitouch events.

    I wasn't sure where you want to go with the structures that hold device state, calibration data, configuration information, etc. Instead of making changes to that stuff, I tried to get it to exhibit reasonable behavior.

     
  • Russell Sears

    Russell Sears - 2008-01-01

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    Version 4 of the patch contains the following bugfixes:

    - Updated the patch to use ds->proximity in a more correct way (a bugfix in the current development version broke version 3 of the patch).

    - Gets rid of some bogus events: This fixes the pen side button under xournal and removes some redundant(?) button released events.
    File Added: linuxwacom-multitouch-fix-stylus-drag-rotate-and-calibration-v4.patch

     
  • Andrew

    Andrew - 2008-01-12

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    Thank you for this patch. I had hacked up #2 a while ago, but your implementation is much better.

    I would really like to separate stylus and mt input as two different Xorg devices. Do you have any idea on how to start doing that? I looked through some of the rest of the sources, but linuxwacom is complex, isn't that well commented, and has to support so many devices that I couldn't figure out anything useful.

    BTW, Thank you for the verbose comments in your patch. It makes it _really_ easy to see what you are doing and why you are doing it.

    (For some reason SF doesn't let me log in atm)
    - Wolf08 (wolf08 a t gmail d o t com)

     
  • Russell Sears

    Russell Sears - 2008-01-12

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    Wolf08,

    I'm happy to hear you're using it. I'm hoping the comments help get it into the development branch. ;)

    My knowledge of the linuxwacom code base is limited to the code the patch touches, so I really don't know where to begin cleaning things up. However, I have thought a bit about what I'd like to see happen:

    I agree that this code needs configuration options, and that the touchscreen and pen should be treated as separate devices. Also, there are other touchscreen drivers for X; perhaps someone should ping the developers for those devices so that touchscreen configuration / behavior can be uniform across vendors.

    When the code is cleaned up, the static variables that the touchscreen uses should be removed, so that multiple screens can coexist, and to be more consistent with the rest of the wacom stuff... Also, it currently loses configuration information across suspend/resume, but that's a "feature"; I'm still seeing occasional spurious touchscreen coordinates (perhaps this is a bug/omission in the packet parsing logic?) which messes up the automatic calibration. (Autocalibration should probably also be removed at some point...)

     
  • Ping Cheng

    Ping Cheng - 2008-08-08

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    As you know that serial touch support is in 0.8.1 now. Have you got a chance to try the new driver recently? I am going to close this track if I don't hear negative replies.

     
  • Ping Cheng

    Ping Cheng - 2008-08-08
    • assigned_to: jjoganic --> pingc
    • status: open --> pending-fixed
     
  • SourceForge Robot

    • status: pending-fixed --> closed-fixed
     
  • SourceForge Robot

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    This Tracker item was closed automatically by the system. It was
    previously set to a Pending status, and the original submitter
    did not respond within 14 days (the time period specified by
    the administrator of this Tracker).

     

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