linux/drivers/input/mouse/alps.h

329 lines
9.9 KiB

Input: ALPS - fix multi-touch decoding on SS4 plus touchpads The fix for handling two-finger scroll (i4a646580f793 - "Input: ALPS - fix two-finger scroll breakage in right side on ALPS touchpad") introduced a minor "typo" that broke decoding of multi-touch events are decoded on some ALPS touchpads. For example, tapping with three-fingers can no longer be used to emulate middle-mouse-button (the kernel doesn't recognize this as the proper event, and doesn't report it correctly to userspace). This affects touchpads that use SS4 "plus" protocol variant, like those found on Dell E7270 & E7470 laptops (tested on E7270). First, probably the code in alps_decode_ss4_v2() for case SS4_PACKET_ID_MULTI used inconsistent indices to "f->mt[]". You can see 0 & 1 are used for the "if" part but 2 & 3 are used for the "else" part. Second, in the previous patch, new macros were introduced to decode X coordinates specific to the SS4 "plus" variant, but the macro to define the maximum X value wasn't changed accordingly. The macros to decode X values for "plus" variant are effectively shifted right by 1 bit, but the max wasn't shifted too. This causes the driver to incorrectly handle "no data" cases, which also interfered with how multi-touch was handled. Fixes: 4a646580f793 ("Input: ALPS - fix two-finger scroll breakage...") Signed-off-by: Nir Perry <nirperry@gmail.com> Reviewed-by: Masaki Ota <masaki.ota@jp.alps.com> Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2018-01-11 23:43:26 -08:00
Input: alps - use more accurate coordinates for first touch in semi-mt mode All alps semi-mt touchpads give us the following data when 2 (or more) fingers are touching: 1 more or less accurate touch for the first finger down, and a bitmap with columns and rows in which 1 or more fingers are seen resulting in a crude (low res) bounding box. So far for v3, rushmore and v4 touchpads we've been reporting the coordinates of 2 opposite corners of the box when 2 fingers are touching. Ignoring the much better resolution data given in the normal position packet. This commit actually uses this data for the first touch, figures out which corner of the bounding box is closest to the first touch, and reports the coordinates of the opposite corner for the second touch, resulting in much better data for the first touch and for the single touch pointer-emulation events. This approach is similar to the one in alps_process_bitmap_dolphin, that function takes the single accurate touch info, calculates the distance to the center of the bounding box, and then puts the 2nd touch mirrored to the center. The downside of that approach is that if both touches move slowly in the same direction, the bounding box will stay the same for a while (as it is low res) and the second touch will thus been seen moving in the opposite direction until the bounding box actually changes, and then the second touch snaps to its new position resulting in a saw tooth pattern in the coordinates for the second touch, hence this new approach. This commit fixes 2 finger scrolling being choppy / jumpy on these touchpads. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2015-05-20 14:41:10 -07:00