RE: [PATCH v2 08/10] Input: elan_i2c - export true width/height
From: 廖崇榮 <hidden>
Date: 2019-05-27 03:55:12
Also in:
linux-devicetree, lkml
Hi -----Original Message----- From: Benjamin Tissoires [mailto:benjamin.tissoires@redhat.com] 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@vger.kernel.org Subject: Re: [PATCH v2 08/10] Input: elan_i2c - export true width/height On Tue, May 21, 2019 at 3:28 PM Benjamin Tissoires [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted> -- 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.cb/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. Cheers, Benjamin
data->input = input;
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2.21.0