diff options
| -rw-r--r-- | drivers/input/mouse/alps.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index d125a019383f..5404a83c2334 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -938,18 +938,36 @@ static int alps_decode_packet_v7(struct alps_fields *f, return 0; if (pkt_id == V7_PACKET_ID_UNKNOWN) return -1; + /* + * NEW packets are send to indicate a discontinuity in the finger + * coordinate reporting. Specifically a finger may have moved from + * slot 0 to 1 or vice versa. INPUT_MT_TRACK takes care of this for + * us. + * + * NEW packets have 3 problems: + * 1) They do not contain middle / right button info (on non clickpads) + * this can be worked around by preserving the old button state + * 2) They do not contain an accurate fingercount, and they are + * typically send when the number of fingers changes. We cannot use + * the old finger count as that may mismatch with the amount of + * touch coordinates we've available in the NEW packet + * 3) Their x data for the second touch is inaccurate leading to + * a possible jump of the x coordinate by 16 units when the first + * non NEW packet comes in + * Since problems 2 & 3 cannot be worked around, just ignore them. + */ + if (pkt_id == V7_PACKET_ID_NEW) + return 1; alps_get_finger_coordinate_v7(f->mt, p, pkt_id); - if (pkt_id == V7_PACKET_ID_TWO || pkt_id == V7_PACKET_ID_MULTI) { - f->left = (p[0] & 0x80) >> 7; - f->right = (p[0] & 0x20) >> 5; - f->middle = (p[0] & 0x10) >> 4; - } + f->left = (p[0] & 0x80) >> 7; + f->right = (p[0] & 0x20) >> 5; + f->middle = (p[0] & 0x10) >> 4; if (pkt_id == V7_PACKET_ID_TWO) f->fingers = alps_get_mt_count(f->mt); - else if (pkt_id == V7_PACKET_ID_MULTI) + else /* pkt_id == V7_PACKET_ID_MULTI */ f->fingers = 3 + (p[5] & 0x03); return 0; |