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platform/surface: surfacepro3_button: don't load on amd variant
The AMD variant of the Surface Laptop report 0 for their OEM platform
revision.  The Surface devices that require the surfacepro3_button
driver do not have the _DSM that gets the OEM platform revision.  If the
method does not exist, load surfacepro3_button.

Fixes: 64dd243 ("platform/x86: surfacepro3_button: Fix device check")
Co-developed-by: Maximilian Luz <luzmaximilian@gmail.com>

Signed-off-by: Sachi King <nakato@nakato.io>
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nakato committed Oct 5, 2021
1 parent 1927c0b commit ac1a977392880456f61e830a95e368cad7a0fa3f
Showing 1 changed file with 6 additions and 24 deletions.
@@ -149,38 +149,20 @@ static int surface_button_resume(struct device *dev)
/*
* Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
* ID (MSHW0040) for the power/volume buttons. Make sure this is the right
* device by checking for the _DSM method and OEM Platform Revision.
* device by checking for the _DSM method and OEM Platform Revision DSM
* function.
*
* Returns true if the driver should bind to this device, i.e. the device is
* either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
*/
static bool surface_button_check_MSHW0040(struct acpi_device *dev)
{
acpi_handle handle = dev->handle;
union acpi_object *result;
u64 oem_platform_rev = 0; // valid revisions are nonzero

// get OEM platform revision
result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
MSHW0040_DSM_REVISION,
MSHW0040_DSM_GET_OMPR,
NULL, ACPI_TYPE_INTEGER);

/*
* If evaluating the _DSM fails, the method is not present. This means
* that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
* should use this driver. We use revision 0 indicating it is
* unavailable.
*/

if (result) {
oem_platform_rev = result->integer.value;
ACPI_FREE(result);
}

dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);

return oem_platform_rev == 0;
// make sure that OEM platform revision DSM call does not exist
return !acpi_check_dsm(handle, &MSHW0040_DSM_UUID,
MSHW0040_DSM_REVISION,
BIT(MSHW0040_DSM_GET_OMPR));
}


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