Consulted with FW team, we suggest re-querying x/y resolution after setting absolute mode. -----Original Message----- From: phoenix [mailto:phoenix@xxxxxxxxxx] Sent: Tuesday, November 29, 2022 11:47 AM To: 'Dmitry Torokhov' <dmitry.torokhov@xxxxxxxxx>; 'Eirin Nya' <nyanpasu256@xxxxxxxxx> Cc: 'linux-input@xxxxxxxxxxxxxxx' <linux-input@xxxxxxxxxxxxxxx>; 'linux-kernel@xxxxxxxxxxxxxxx' <linux-kernel@xxxxxxxxxxxxxxx>; 'Josh.Chen' <josh.chen@xxxxxxxxxx> Subject: RE: [PATCH V2 3/3] Input: elantech - Fix incorrectly halved touchpad range on ELAN v3 touchpads Loop Josh -----Original Message----- From: Dmitry Torokhov [mailto:dmitry.torokhov@xxxxxxxxx] Sent: Tuesday, November 29, 2022 1:59 AM To: Eirin Nya <nyanpasu256@xxxxxxxxx>; Phoenix Huang <phoenix@xxxxxxxxxx> Cc: linux-input@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx Subject: Re: [PATCH V2 3/3] Input: elantech - Fix incorrectly halved touchpad range on ELAN v3 touchpads On Mon, Nov 28, 2022 at 09:57:51AM -0800, Dmitry Torokhov wrote: > On Fri, Oct 14, 2022 at 04:15:33AM -0700, Eirin Nya wrote: > > On Linux 5.19.10, on my laptop (Dell Inspiron 15R SE 7520) with an > > Elan > > v3 touchpad (dmesg says "with firmware version 0x450f02"), the > > reported size of my touchpad (in userspace by calling > > mtdev_configure() and libevdev_get_abs_maximum(), in kernel space > > elantech_device_info::x_max/y_max, either way 1470 by 700) is half > > that of the actual touch range (2940 by 1400), and the upper half of > > my touchpad reports negative values. As a result, with the Synaptics > > or libinput X11 driver set to edge scrolling mode, the entire right > > half of my touchpad has x-values past evdev's reported maximum size, > > and acts as a giant scrollbar! > > > > The problem is that elantech_setup_ps2() -> > > elantech_set_absolute_mode() sets up absolute mode and doubles the > > hardware resolution (doubling the hardware's maximum reported x/y > > coordinates and its response to ETP_FW_ID_QUERY), *after* > > elantech_query_info() fetches the touchpad coordinate system size > > using ETP_FW_ID_QUERY, which gets cached and reported to userspace > > through ioctl(fd, EVIOCGABS(ABS_X/Y), ...). So the touchpad size > > reported to userspace (and used to subtract vertical coordinates from) is half the maximum position of actual touches. > > > > This patch splits out a function elantech_query_range_v3() which > > fetches > > *only* ETP_FW_ID_QUERY (touchpad size), and calls it a second time > > if > > elantech_set_absolute_mode() enables double-size mode. This means > > the first call is redundant and wasted if a second call occurs, but > > this minimizes the need to restructure the driver. > > If the setting is indeed double resolution, can we simply multiply > x_max and y_max by 2 instead of re-querying it? > > Also let's try adding one of Elan engineers for their take in this. > Phoenix, do you have any suggestions please? Argh, adding Phoenix for real now. > > > > > Link: > > https://lore.kernel.org/linux-input/CAL57YxZNutUVxBtvbVWKMw-V2kqeVB5 > > kTQ5BFdJmN=mdPq8Q8Q@xxxxxxxxxxxxxx/ > > Link: > > https://lore.kernel.org/linux-input/20221008093437.72d0f6b0@dell-voi > > d.nyanpasu256.gmail.com.beta.tailscale.net/ > > Fixes: 37548659bb22 ("Input: elantech - query the min/max > > information beforehand too") > > Signed-off-by: Eirin Nya <nyanpasu256@xxxxxxxxx> > > --- > > > > Notes: > > Should we move (elantech_set_absolute_mode -> > > elantech_write_reg(...0x0b or 0x01)) *earlier* into elantech_query_info() > > before "query range information"? See discussion at > > > > https://lore.kernel.org/linux-input/20221008093437.72d0f6b0@dell-voi > > d.nyanpasu256.gmail.com.beta.tailscale.net/ > > > > drivers/input/mouse/elantech.c | 30 ++++++++++++++++++++++++++---- > > 1 file changed, 26 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/input/mouse/elantech.c > > b/drivers/input/mouse/elantech.c index 263779c031..a2176f0fd3 100644 > > --- a/drivers/input/mouse/elantech.c > > +++ b/drivers/input/mouse/elantech.c > > @@ -1006,6 +1006,9 @@ static void elantech_set_rate_restore_reg_07(struct psmouse *psmouse, > > psmouse_err(psmouse, "restoring reg_07 failed\n"); } > > > > +static int elantech_query_range_v3(struct psmouse *psmouse, > > + struct elantech_device_info *info); > > + > > /* > > * Put the touchpad into absolute mode > > */ > > @@ -1047,6 +1050,14 @@ static int elantech_set_absolute_mode(struct psmouse *psmouse) > > if (elantech_write_reg(psmouse, 0x10, etd->reg_10)) > > rc = -1; > > > > + /* > > + * If we boost hardware resolution, we have to re-query > > + * info->x_max and y_max. > > + */ > > + if (etd->info.set_hw_resolution) > > + if (elantech_query_range_v3(psmouse, &etd->info)) > > + rc = -1; > > + > > break; > > > > case 4: > > @@ -1671,6 +1682,20 @@ static int elantech_set_properties(struct elantech_device_info *info) > > return 0; > > } > > > > +static int elantech_query_range_v3(struct psmouse *psmouse, > > + struct elantech_device_info *info) { > > + unsigned char param[3]; > > + > > + if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param)) > > + return -EINVAL; > > + > > + info->x_max = (0x0f & param[0]) << 8 | param[1]; > > + info->y_max = (0xf0 & param[0]) << 4 | param[2]; > > + > > + return 0; > > +} > > + > > static int elantech_query_info(struct psmouse *psmouse, > > struct elantech_device_info *info) { @@ -1826,11 +1851,8 > > @@ static int elantech_query_info(struct psmouse *psmouse, > > break; > > > > case 3: > > - if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param)) > > + if (elantech_query_range_v3(psmouse, info)) > > return -EINVAL; > > - > > - info->x_max = (0x0f & param[0]) << 8 | param[1]; > > - info->y_max = (0xf0 & param[0]) << 4 | param[2]; > > break; > > > > case 4: > > -- > > 2.38.0 > > > > Thanks. > > -- > Dmitry -- Dmitry
