Hi Dmity, Sorry for late reply. > + if (packet[4] == 0x80 || packet[5] == 0x80 || > + packet[1] >> 7 == packet[4] >> 7 || "I think this will reject X coordinates in range [0, 127]. Is this really what is needed? What kind of patterns are you observing when firmware misreports coordinates?" this will reject X in range [128, 256] and [-128, -256]. This patch prevent cursor suddenly jump to screen edge or corner. The patterns we observing as below: 1. x (packet[4]) or y (packet[5]) is 0x80, ex: [xx xx xx xx 80 80] 2. ~x sign bit is same as MSB(most significant bit) of x, ex: [30 00 00 06 00 00] 3. ~y sign bit is same as MSB of y, ex: [30 00 00 06 fa 00] Best regards, Phoenix Huang -----Original Message----- From: Dmitry Torokhov [mailto:dmitry.torokhov@xxxxxxxxx] Sent: Tuesday, August 31, 2021 4:24 AM To: phoenix <phoenix@xxxxxxxxxx> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-input@xxxxxxxxxxxxxxx; jingle.wu@xxxxxxxxxx; josh.chen@xxxxxxxxxx; dave.wang@xxxxxxxxxx Subject: Re: [PATCH] Input: elantench - Fix the firmware misreport coordinates for trackpoint occasionally. Hi Phoenix, On Mon, Aug 30, 2021 at 08:19:48PM +0800, phoenix wrote: > Hi Dmitry, > > Would you review this patch, thanks > > Best regards, > Phoenix Huang > > -----Original Message----- > From: Phoenix Huang [mailto:phoenix@xxxxxxxxxx] > Sent: Thursday, July 29, 2021 9:10 AM > To: linux-kernel@xxxxxxxxxxxxxxx; linux-input@xxxxxxxxxxxxxxx; > dmitry.torokhov@xxxxxxxxx > Cc: jingle.wu@xxxxxxxxxx; josh.chen@xxxxxxxxxx; dave.wang@xxxxxxxxxx; > Phoenix Huang <phoenix@xxxxxxxxxx> > Subject: [PATCH] Input: elantench - Fix the firmware misreport > coordinates for trackpoint occasionally. > > Signed-off-by: Phoenix Huang <phoenix@xxxxxxxxxx> > --- > drivers/input/mouse/elantech.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/input/mouse/elantech.c > b/drivers/input/mouse/elantech.c index 2d0bc029619f..07e1098f2d31 > 100644 > --- a/drivers/input/mouse/elantech.c > +++ b/drivers/input/mouse/elantech.c > @@ -517,6 +517,17 @@ static void elantech_report_trackpoint(struct > psmouse *psmouse, > case 0x16008020U: > case 0x26800010U: > case 0x36808000U: > + > + /* This firmware misreport coordinates for trackpoint > occasionally. > + * So we discard these packets by pattern to prevent cursor > jumps. > + */ > + if (packet[4] == 0x80 || packet[5] == 0x80 || > + packet[1] >> 7 == packet[4] >> 7 || I think this will reject X coordinates in range [0, 127]. Is this really what is needed? What kind of patterns are you observing when firmware misreports coordinates? Thanks. -- Dmitry
