Re: [PATCH 1/1] Force ELAN06FA touchpad I2C bus freq to 100KHz

Mika Westerberg
2025-01-05T08:34:01Z

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