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    SubjectRe: Mouse and keyboard drivers in the Linux Kernel?
    Kendall Bennett wrote:
    > Hi All,
    > We are getting close to finishing the port of our SciTech Multi-
    > platform Graphics Library to Linux (free Open Source under our
    > modified mozilla PL). One thing has been bothering me for some time
    > is that Linux does not appear to have a *full* mouse driver built
    > into the kernel. There is the /dev/mouse device you can use to
    > communicate with the currently configured mouse, however this device
    > simply passes back the raw mouse protocol data and we need to know
    > about *all* the different types of mice that can be attached, and to
    > somehow figure out what one is actually connected.
    This is normal. AFAIK this is the documented behavior when you read
    directly from a serial port.

    > This is a major pain, so I was wondering if there really was a real
    > mouse driver in the Linux kernel, or if people are interested in
    > building one? Specifically I want a device that maintains a queue of
    > events internally including mouse up, mouse down and mouse movement
    > events (including a 1ms time stamp for every event so we can tell how
    > far apart the events were). Then our MGL code will only need to
    > connect to the mouse device and read the events from the queue to get
    > the real data we need. Oh, and using the GPM libraries is not
    > suitable because GPM is not always installed, and this stuff should
    > really be in the kernel anyway.
    Mice are handled from userspace; either the gpm daemon or the X server.
    I really see no reason to have mouse drivers in the kernel, we should
    only have the bare minimum needed to access them from userspace, e.g.
    serial port/usb/busmouse stuff.

    There are mouse routines you can link to from userspace distributed with
    gpm, (libgpm) I suggest that you snag the source and take a look. Of
    course, this is assuming that you want to use mice for the text console.

    You might also want to take a look at what the GGI/KGI people are doing
    WRT mice. They seem to have a pretty good thing going with video and

    > Likewise another thing that bothers me is the keyboard driver we have
    > in the MGL. The MGL's event mechanism requires a keyboard driver that
    > allows us to get KEYUP, KEYDOWN and KEYREPEAT events along with a 1ms
    > time stamp for all key events. We also need to know the real scan
    > code of the keypress, along with the correct ASCII translation for
    > the key. Right now the kernel keyboard driver does not provide such
    > functionality, so we have to run the keyboard in RAW mode so we can
    > process the up/down events ourselves. This works fine (but we need a
    > separate thread processing input so we can get the time stamps),
    > however it also means we are not responsible for doing the scancode-
    > >ASCII translations. This is something we should not be doing in our
    > code, and once again something that should be handled in the kernel.
    Definitely look at GGI/KGI. You might also want to sift through the
    SVGAlib source, as I believe that it handles mice and other input.

    | Ian Eure
    <> |
    | Network Administrator, Cross Sound Appraisal
    Company |
    | "Believe it or not, there's more to being a sysadmin than
    rabid |
    | technophilia." --Annalee Newitz, "Invisible
    Heroes" |

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