Hi, On 2/4/22 18:39, Benjamin Tissoires wrote: > Hi, > > [adding Dmitry, the maintainer of the input tree and Hans, a colleague of mine] > > On Fri, Feb 4, 2022 at 5:57 PM Takashi Iwai <tiwai@xxxxxxx> wrote: >> >> Hi, >> >> we've got a bug report on openSUSE Bugzilla about the broken touchpad >> on Lenovo Yoga Slim 7: >> https://bugzilla.opensuse.org/show_bug.cgi?id=1193064 >> >> The touchpad is an Elantech one, connected over i2c, and there are two >> drivers supporting it. Unfortunately, the default one the system >> binds, elan-i2c input driver, doesn't seem working properly, while >> i2c-hid driver works. > > Hans, we do have a similar bug on RHEL at > https://bugzilla.redhat.com/show_bug.cgi?id=2029078 (sorry, private > bug). > > IIRC you worked on the discrimination between i2c-hid and elan_i2c (I > might be completely wrong though). Yes I did work on that, but then the other way around making sure that the i2c-hid driver would not bind to some devices which need the elan_i2c touch*pad* driver. And indeed as Dmitry points out: > I believe we need to do what Hans did for Elan Touch*screen* driver and > avoid binding to the device if it has i2c-hid-specific _DMS in ACPI. > I.e. we need to replicate elants_acpi_is_hid_device(). > > Even better would be to factor it out, maybe not into a shared module > but simply shared header with static inline function that we could share > between elan drivers and maybe others as well. I did fix a similar problem for the touchscreen driver last year or so. I agree with Dmitry that we should try to avoid DMI matching here; and I also agree that having some header with a static inline acpi_is_hid_device() device helper would be good. I'm a bit worried about the acpi_is_hid_device() approach though, there is a lot of copy and pasting going on when vendors create ACPI tables and sometimes a "PNP0C50" CID is present combined with a valid i2c-hid _DSM method even though the device is not an i2c-hid device, also see the i2c_hid_acpi_blacklist[] in drivers/hid/i2c-hid/i2c-hid-acpi.c . It seems to me that the problem is that the Lenovo Yoga Slim 7 is using what seems to be a very generic "ELAN0000" ACPI hardware id instead of one of the many more specific ones. So we could limit the acpi_is_hid_device() check to just the "ELAN0000" ACPI hardware id I guess? So I see the following 2 options: 1. Add an unconditional acpi_is_hid_device() check to elan_probe() and watch out for any bug-reports that this is causing breakage elsehwere 2. Add an acpi_is_hid_device() check to elan_probe() for ACPI enumerated touchpads with a hardware-id of ELAN0000 only; and still watch out for any bug-reports that this is causing breakage elsehwere just to be sure Regards, Hans >> I'm not sure what's the best fix for this, but below a quick >> workaround using a deny list with DMI matching. >> If this is OK, I can resubmit the patch for merging. >> >> Any comments appreciated. >> >> >> thanks, >> >> Takashi >> >> -- 8< -- >> From: Takashi Iwai <tiwai@xxxxxxx> >> Subject: [PATCH] Input: elan_i2c: Add deny list for Lenovo Yoga Slim 7 >> >> The touchpad on Lenovo Yoga Slim 7 doesn't work well with elan-i2c but >> rather better with i2c-hid. Add a deny list for avoiding to bind with >> elan-i2c. >> >> BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1193064 >> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> >> --- >> drivers/input/mouse/elan_i2c_core.c | 19 +++++++++++++++++++ >> 1 file changed, 19 insertions(+) >> >> diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c >> index 47af62c12267..fd08481f7aea 100644 >> --- a/drivers/input/mouse/elan_i2c_core.c >> +++ b/drivers/input/mouse/elan_i2c_core.c >> @@ -18,6 +18,7 @@ >> #include <linux/acpi.h> >> #include <linux/delay.h> >> #include <linux/device.h> >> +#include <linux/dmi.h> >> #include <linux/firmware.h> >> #include <linux/i2c.h> >> #include <linux/init.h> >> @@ -1222,6 +1223,20 @@ static void elan_disable_regulator(void *_data) >> regulator_disable(data->vcc); >> } >> >> +static const struct dmi_system_id elan_i2c_denylist[] __initconst = { >> +#if IS_ENABLED(CONFIG_I2C_HID_ACPI) >> + { >> + /* Lenovo Yoga Slim 7 is better supported by i2c-hid */ >> + .matches = { >> + DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), >> + DMI_MATCH(DMI_PRODUCT_NAME, "82A3"), >> + DMI_MATCH(DMI_PRODUCT_VERSION, "Yoga Slim 7 14ITL05"), >> + }, >> + }, >> +#endif >> + { } >> +}; >> + >> static int elan_probe(struct i2c_client *client, >> const struct i2c_device_id *dev_id) >> { >> @@ -1233,6 +1248,10 @@ static int elan_probe(struct i2c_client *client, >> >> if (IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_I2C) && >> i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { >> + if (dmi_check_system(elan_i2c_denylist)) { >> + dev_info(dev, "Hits deny list, skipping\n"); >> + return -ENODEV; >> + } >> transport_ops = &elan_i2c_ops; >> } else if (IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) && >> i2c_check_functionality(client->adapter, >> -- >> 2.31.1 >> >> >> >> >> >> >> >
