Preliminary support for I2C HID touchpads of Intel Tigerlake+ notebooks #5195
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chelmuth
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Apr 24, 2024
Discovered on Tigerlake (Fujitsu U7411) and Alderlake (Framework Gen12) notebook devices. Issue #5195
chelmuth
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Apr 24, 2024
Discovered on Tigerlake (Fujitsu U7411) and Alderlake (Framework Gen12) notebook devices. Issue #5195
chelmuth
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Apr 24, 2024
The ported i2c_hid driver contains driver code for the "Intel Tigerlake/Alderlake PCH pinctrl/GPIO" device. Unfortunately, acpica driver also accesses the same device on Lid open/close via ACPI AML code of the DSDT table to read out the state of a GPIO pin connected to the notebook lid. This would fail as I/O memory is handed out only once and cannot be shared. The workaround disables the region check for the specified GPIO I/O memory regions and provides both drivers shared access to the regions. This is a preliminary workaround. A general solution should separate the GPIO driver into a component (e.g., platform driver) that regulates accesses by i2c_hid and acpica. Issue #5195
chelmuth
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chelmuth
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Apr 25, 2024
Discovered on Tigerlake (Fujitsu U7411) and Alderlake (Framework Gen12) notebook devices. Issue #5195
chelmuth
added a commit
that referenced
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Apr 25, 2024
Discovered on Tigerlake (Fujitsu U7411) and Alderlake (Framework Gen12) notebook devices. Issue #5195
chelmuth
added a commit
that referenced
this issue
Apr 25, 2024
The ported i2c_hid driver contains driver code for the "Intel Tigerlake/Alderlake PCH pinctrl/GPIO" device. Unfortunately, acpica driver also accesses the same device on Lid open/close via ACPI AML code of the DSDT table to read out the state of a GPIO pin connected to the notebook lid. This would fail as I/O memory is handed out only once and cannot be shared. The workaround disables the region check for the specified GPIO I/O memory regions and provides both drivers shared access to the regions. This is a preliminary workaround. A general solution should separate the GPIO driver into a component (e.g., platform driver) that regulates accesses by i2c_hid and acpica. Issue #5195
chelmuth
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Apr 25, 2024
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The I2C HID support is a conglomerate of the following basic mechanisms.
PCH GPIO is a platform device (e.g., INT34C5) with a spec-defined configuration that can be retrieved from ACPI tables.
The I2C master controller is a (pseudo-)PCI device, mostly with unsufficiently initialized BARs.
The actual HID device (CID PNP0C50) is accessible via the mechanisms above and its configuration can be retrieved from ACPI resources and device-specific methods.
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