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? > > Link: https://lore.kernel.org/linux-input/CAL57YxZNutUVxBtvbVWKMw-V2kqeVB5kTQ5BFdJmN=mdPq8Q8Q@xxxxxxxxxxxxxx/ > Link: https://lore.kernel.org/linux-input/20221008093437.72d0f6b0@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > 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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > > 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
