Cursor does not move left/right using touchpad on 2.6.22-20080123.4 and newer master kernels
denver at ossguy.com
Sun May 25 00:13:58 EDT 2008
On Sat, May 3, 2008 at 6:25 PM, Denver Gingerich <denver at ossguy.com> wrote:
> On Fri, May 2, 2008 at 10:42 PM, Denver Gingerich <denver at ossguy.com> wrote:
>> On Thu, May 1, 2008 at 11:38 PM, Denver Gingerich <denver at ossguy.com> wrote:
>> > On 2.6.22-20080123.4 and newer master kernels (specifically
>> > 2.6.22-20080123.4, 2.6.25-20080430.1, 2.6.25-20080501.2, and
>> > 2.6.25-20080501.3), the cursor cannot move from side to side with the
>> > touchpad, only up and down. Using a USB mouse works fine.
>> > Here is an example X session:
>> > 1. start X, cursor is in the center of the screen; touchpad has not been touched
>> > 2. touch touchpad, cursor immediately jumps to the left side of the screen
> See below for more details on Step 2.
>> > 3. move around on touchpad, cursor stays "stuck" to the left side of
>> > the screen, but moves up and down relative to how much vertical
>> > touchpad movement there is
>> > 4a. release finger from touchpad, cursor immediately jumps to the
>> > top-left corner of the screen (this may not be exactly the top-left
>> > corner, but it is always on the left-most column of pixels within the
>> > top 50-100 rows of pixels)
>> > 4b. move finger across right edge of touchpad, cursor moves very
>> > quickly from left to right across the screen (there appears to be a
>> > small area between the touchpad and the right third of the drawing pad
>> > where left to right motion is detected)
>> > Performing steps 2-4 consistently gives the same results within the
>> > same X session and across reboots.
>> The problem is present in 2.6.22-2008115.1 but not in
> The problem is also present in 2.6.22-20080114.2. So the problem is
> between the following commits:
> Here are some additional details for Step 2 (touch touchpad): the
> vertical position that the cursor jumps to is correlated with the
> location on the touchpad that my finger is on. For example, if I
> touch the top part of the touchpad, the cursor will jump to the top
> part of the screen. So there is some absolute positioning going on.
> Additionally, a button press is registered when I touch the touchpad
> (even when I don't click the button) and a button release is
> registered when I take my finger off the touchpad. So moving my
> finger on the touchpad is essentially dragging whatever happens to be
> under the cursor. The button press is registered after the cursor
> jumps to its new position on the screen following my finger touching
> the touchpad.
This issue is present in the 2.6.26-rc3 master kernel (not surprising
as mouse/olpc.c hasn't changed since 2.6.25).
I now have access to a development environment so I should be able to
compile the intermediate commits (between f870978 and cb6634d) to
diagnose the problem further. I will report back when I have more
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