[NATTY][PATCH] HID: magicmouse: Don't report REL_{X, Y} for Magic Trackpad

Chase Douglas chase.douglas at canonical.com
Tue Jan 4 14:28:00 UTC 2011

With the recent switch to having the hid layer handle standard axis
initialization, the Magic Trackpad now reports relative axes. This would
be fine in the normal mode, but the driver puts the device in multitouch
mode where no relative events are generated. Also, userspace software
depends on accurate axis information for device type detection. Thus,
ignoring the relative axes from the Magic Trackpad is best.

Signed-off-by: Chase Douglas <chase.douglas at canonical.com>
Signed-off-by: Jiri Kosina <jkosina at suse.cz>

This got stuck near the end of the .37 development cycle and didn't make it in
time. Since the next release with this will probably be .38-rc1 in a few weeks,
please include the patch in the Natty kernel in the meantime as it is causing
issues for our own development efforts.


 drivers/hid/hid-magicmouse.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index e6dc151..ed732b7 100644
--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -433,6 +433,11 @@ static int magicmouse_input_mapping(struct hid_device *hdev,
 	if (!msc->input)
 		msc->input = hi->input;
+	/* Magic Trackpad does not give relative data after switching to MT */
+	if (hi->input->id.product == USB_DEVICE_ID_APPLE_MAGICTRACKPAD &&
+	    field->flags & HID_MAIN_ITEM_RELATIVE)
+		return -1;
 	return 0;

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