Re: [PATCH v2 1/2] platform: Fix device check for surfacepro3_button
From: Yu Chen <yu.c.chen@intel.com>
Date: 2019-07-02 01:04:25
Also in:
lkml, platform-driver-x86
Hi, On Tue, Jul 02, 2019 at 02:37:39AM +0200, Maximilian Luz wrote:
Do not use the surfacepro3_button driver on newer Microsoft Surface models, only use it on the Surface Pro 3 and 4. Newer models (5th, 6th and possibly future generations) use the same device as the Surface Pro 4 to represent their volume and power buttons (MSHW0040), but their acutal implementation is significantly different. This patch ensures that the surfacepro3_button driver is only used on the Pro 3 and 4 models, allowing a different driver to bind on other models.
This method overall looks ok to me.
quoted hunk ↗ jump to hunk
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com> --- drivers/platform/x86/surfacepro3_button.c | 38 +++++++++++++++++++++++ 1 file changed, 38 insertions(+)diff --git a/drivers/platform/x86/surfacepro3_button.c b/drivers/platform/x86/surfacepro3_button.c index 47c6d000465a..0e2c7dfafd9f 100644 --- a/drivers/platform/x86/surfacepro3_button.c +++ b/drivers/platform/x86/surfacepro3_button.c@@ -20,6 +20,12 @@ #define SURFACE_BUTTON_OBJ_NAME "VGBI" #define SURFACE_BUTTON_DEVICE_NAME "Surface Pro 3/4 Buttons" +#define MSHW0040_DSM_REVISION 0x01 +#define MSHW0040_DSM_GET_OMPR 0x02 // get OEM Platform Revision +static const guid_t MSHW0040_DSM_UUID = + GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65, + 0x49, 0x80, 0x35); + #define SURFACE_BUTTON_NOTIFY_TABLET_MODE 0xc8 #define SURFACE_BUTTON_NOTIFY_PRESS_POWER 0xc6@@ -142,6 +148,34 @@ static int surface_button_resume(struct device *dev) } #endif +/* + * 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. + */ +static int surface_button_check_MSHW0040(struct acpi_device *dev) +{ + acpi_handle handle = dev->handle; + union acpi_object *result; + u64 oem_platform_rev = 0; + + // get OEM platform revision + result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID, + MSHW0040_DSM_REVISION, + MSHW0040_DSM_GET_OMPR, + NULL, ACPI_TYPE_INTEGER); +
Does it mean, only 5th, 6th and newer platforms have OEM platform revision? 3rd/4th will get NULL result? Or the opposite?
+ 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 ? 0 : -ENODEV;if 3rd/4th do not have this oem rev information while 5th/newer have, why the latter returns NODEV(it actually has this info)?
quoted hunk ↗ jump to hunk
+} + + static int surface_button_add(struct acpi_device *device) { struct surface_button *button;@@ -154,6 +188,10 @@ static int surface_button_add(struct acpi_device *device) strlen(SURFACE_BUTTON_OBJ_NAME))) return -ENODEV; + error = surface_button_check_MSHW0040(device); + if (error) + return error; +
ditto, 3rd/4th get error=0?
button = kzalloc(sizeof(struct surface_button), GFP_KERNEL); if (!button) return -ENOMEM; -- 2.22.0
Best, Yu