| Message ID | 20250103051657.211966-2-rha051117@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] Force ELAN06FA touchpad I2C bus freq to 100KHz | expand |
On Fri, Jan 03, 2025 at 05:46:27PM -0600, R Ha wrote: > Hello, > > Thanks for reading my patch! > > On Fri, Jan 3, 2025 at 3:33 AM Mika Westerberg > <mika.westerberg@linux.intel.com> wrote: > > What are those "some devices" and "some controllers"? > > The "Some Devices" are the Lenovo V15 G4 IRU, which I use, and > potentially the Lenovo V15 G4 AMN and Lenovo Ideapad Slim 3 15IAH8 as > well (based on issue reports from other users [1]). > The "Some Controllers" are the Designware I2C controller. > > Sorry for not putting this in the commit message; I had tried to > follow the comments for the quirk I copied in Commit 7574c0db2e68c > ("i2c: acpi: Force bus speed to 400KHz if a Silead touchscreen is > present"), which left them out. In general it is good to follow the existing changelogs but in this case I would prefer to add the details of the system in question (so we know what systems the quirk is applied to). > On Fri, Jan 3, 2025 at 3:33 AM Mika Westerberg > <mika.westerberg@linux.intel.com> wrote: > > Can you add the ACPI table snippet here too for reference? > > I believe this is the correct snippet in my ACPI table (Again, V15 G4 > IRU). Tried to edit it down as much as I could, hopefully this tells > everything. Please let me know how I should attach a longer snippet or > the full ACPI table if needed. Okay thanks for sharing. I don't see the "SPED" beeing assigned in the below snipped though. I would expect this works in Windows? Have you checked if it uses 100 kHz or 400kHz there? > Scope (_SB.PC00.I2C1) > { > [...] > Device (TPD0) > { > [...] > CreateWordField (SBFB, \_SB.PC00.I2C1.TPD0._Y53._ADR, BADR) > // _ADR: Address > CreateDWordField (SBFB, \_SB.PC00.I2C1.TPD0._Y53._SPE, SPED) > // _SPE: Speed > CreateWordField (SBFG, 0x17, INT1) > CreateDWordField (SBFI, \_SB.PC00.I2C1.TPD0._Y54._INT, INT2) > // _INT: Interrupts > Method (_INI, 0, NotSerialized) // _INI: Initialize > { > If ((OSYS < 0x07DC)) > { > SRXO (0x09080011, One) > } > > INT1 = GNUM (0x09080011) > INT2 = INUM (0x09080011) > If ((TPTY == One)) > { > _HID = "ELAN06FA" > _SUB = "ELAN0001" > BADR = 0x15 > HID2 = One > Return (Zero) > } > [...] > } > > Name (_HID, "XXXX0000") // _HID: Hardware ID > Name (_CID, "PNP0C50" /* HID Protocol Device (I2C bus) */) // > _CID: Compatible ID > Name (_SUB, "XXXX0000") // _SUB: Subsystem ID > Name (_S0W, 0x03) // _S0W: S0 Device Wake State > Method (_DSM, 4, Serialized) // _DSM: Device-Specific Method > { > If ((Arg0 == HIDG)) > { > Return (HIDD (Arg0, Arg1, Arg2, Arg3, HID2)) > } > > If ((Arg0 == TP7G)) > { > Return (TP7D (Arg0, Arg1, Arg2, Arg3, SBFB, SBFG)) > } > > Return (Buffer (One) > { > 0x00 // . > }) > } > [...] > Method (_CRS, 0, NotSerialized) // _CRS: Current Resource Settings > { > If ((OSYS < 0x07DC)) > { > Return (SBFI) /* \_SB_.PC00.I2C1.TPD0.SBFI */ > } > > If ((TPDM == Zero)) > { > Return (ConcatenateResTemplate (I2CM (I2CX, BADR, SPED), SBFG)) > } > > Return (ConcatenateResTemplate (I2CM (I2CX, BADR, SPED), SBFI)) > } > [...] > } > } > > For comparison, the properties for a device that I think did set a > proper speed was like this: > If ((TPNP == 0xD64D)) > { > _HID = "GTCH7503" > HID2 = One > BADR = 0x10 > SPED = 0x000F4240 > Return (Zero) > } > > [1]: https://bbs.archlinux.org/viewtopic.php?id=297092
diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c index 14ae0cfc325e..b10f52e12fe8 100644 --- a/drivers/i2c/i2c-core-acpi.c +++ b/drivers/i2c/i2c-core-acpi.c @@ -355,6 +355,18 @@ static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = { {} }; +static const struct acpi_device_id i2c_acpi_force_100khz_device_ids[] = { + /* + * When a 400KHz freq is used on this model of ELAN touchpad instead + * of 100Khz, excessive smoothing (similar to when there is noise in + * the signal) is intermittently applied. As some devices' ACPI + * tables do not specify the 100KHz frequency requirement, it is + * necessary to force the speed to 100KHz. + */ + { "ELAN06FA", 0 }, + {} +}; + static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level, void *data, void **return_value) { @@ -373,6 +385,9 @@ static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level, if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0) lookup->force_speed = I2C_MAX_FAST_MODE_FREQ; + if (acpi_match_device_ids(adev, i2c_acpi_force_100khz_device_ids) == 0) + lookup->force_speed = I2C_MAX_STANDARD_MODE_FREQ; + return AE_OK; }
Some devices do not define valid bus frequencies for the ELAN06FA touchpad in their ACPI table, and some controllers run them at 400KHz by default. The 06FA touchpad exhibits excessive smoothing behaviors when run at 400KHz, so force the bus frequency to 100KHz. Signed-off-by: Randolph Ha <rha051117@gmail.com> --- drivers/i2c/i2c-core-acpi.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)