On Mon, 27 May 2019 at 18:21, Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote: > > Hi Benjamin, KT, > > On Mon, May 27, 2019 at 11:55:01AM +0800, 廖崇榮 wrote: > > Hi > > > > -----Original Message----- > > From: Benjamin Tissoires [mailto:benjamin.tissoires@xxxxxxxxxx] > > Sent: Friday, May 24, 2019 5:37 PM > > To: Dmitry Torokhov; KT Liao; Rob Herring; Aaron Ma; Hans de Goede > > Cc: open list:HID CORE LAYER; lkml; devicetree@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH v2 08/10] Input: elan_i2c - export true width/height > > > > On Tue, May 21, 2019 at 3:28 PM Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> wrote: > > > > > > The width/height is actually in the same unit than X and Y. So we > > > should not tamper the data, but just set the proper resolution, so > > > that userspace can correctly detect which touch is a palm or a finger. > > > > > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> > > > > > > -- > > > > > > new in v2 > > > --- > > > drivers/input/mouse/elan_i2c_core.c | 11 ++++------- > > > 1 file changed, 4 insertions(+), 7 deletions(-) > > > > > > diff --git a/drivers/input/mouse/elan_i2c_core.c > > > b/drivers/input/mouse/elan_i2c_core.c > > > index 7ff044c6cd11..6f4feedb7765 100644 > > > --- a/drivers/input/mouse/elan_i2c_core.c > > > +++ b/drivers/input/mouse/elan_i2c_core.c > > > @@ -45,7 +45,6 @@ > > > #define DRIVER_NAME "elan_i2c" > > > #define ELAN_VENDOR_ID 0x04f3 > > > #define ETP_MAX_PRESSURE 255 > > > -#define ETP_FWIDTH_REDUCE 90 > > > #define ETP_FINGER_WIDTH 15 > > > #define ETP_RETRY_COUNT 3 > > > > > > @@ -915,12 +914,8 @@ static void elan_report_contact(struct elan_tp_data *data, > > > return; > > > } > > > > > > - /* > > > - * To avoid treating large finger as palm, let's reduce the > > > - * width x and y per trace. > > > - */ > > > - area_x = mk_x * (data->width_x - ETP_FWIDTH_REDUCE); > > > - area_y = mk_y * (data->width_y - ETP_FWIDTH_REDUCE); > > > + area_x = mk_x * data->width_x; > > > + area_y = mk_y * data->width_y; > > > > > > major = max(area_x, area_y); > > > minor = min(area_x, area_y); @@ -1123,8 +1118,10 @@ > > > static int elan_setup_input_device(struct elan_tp_data *data) > > > ETP_MAX_PRESSURE, 0, 0); > > > input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, > > > ETP_FINGER_WIDTH * max_width, 0, 0); > > > + input_abs_set_res(input, ABS_MT_TOUCH_MAJOR, data->x_res); > > > input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, > > > ETP_FINGER_WIDTH * min_width, 0, 0); > > > + input_abs_set_res(input, ABS_MT_TOUCH_MINOR, data->y_res); > > > > I had a chat with Peter on Wednesday, and he mentioned that this is dangerous as Major/Minor are max/min of the width and height. And given that we might have 2 different resolutions, we would need to do some computation in the kernel to ensure the data is correct with respect to the resolution. > > > > TL;DR: I don't think we should export the resolution there :( > > > > KT, should I drop the patch entirely, or is there a strong argument for keeping the ETP_FWIDTH_REDUCE around? > > I suggest you apply the patch, I have no idea why ETP_FWIDTH_REDUCE existed. > > Our FW team know nothing about ETP_FWIDTH_REDUCE ether. > > > > The only side effect will happen on Chromebook because such computation have stayed in ChromeOS' kernel for four years. > > Chrome's finger/palm threshold may be different from other Linux distribution. > > We will discuss it with Google once the patch picked by chrome and cause something wrong. > > Chrome has logic that contact with maximum major/minor is treated as a > palm, so here the driver (which originally came from Chrome OS) > artificially reduces the contact size to ensure that palm rejection > logic does not trigger. > > I'm adding Harry to confirm whether we are still using this logic and to > see if we can adjust it to be something else. I'm not very familiar with our touchpad code, so adding Sean O'Brien, who is.
