[PATCH 4.19 151/267] platform/x86: intel-vbtn: Do not advertise switches to userspace if they are not there

Greg Kroah-Hartman
2020-06-19T16:18:17Z

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 990fbb48067bf8cfa34b7d1e6e1674eaaef2f450 ]

Commit de9647efeaa9 ("platform/x86: intel-vbtn: Only activate tablet mode
switch on 2-in-1's") added a DMI chassis-type check to avoid accidentally
reporting SW_TABLET_MODE = 1 to userspace on laptops (specifically on the
Dell XPS 9360), to avoid e.g. userspace ignoring touchpad events because
userspace thought the device was in tablet-mode.

But if we are not getting the initial status of the switch because the
device does not have a tablet mode, then we really should not advertise
the presence of a tablet-mode switch to userspace at all, as userspace may
use the mere presence of this switch for certain heuristics.

Fixes: de9647efeaa9 ("platform/x86: intel-vbtn: Only activate tablet mode switch on 2-in-1's")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/platform/x86/intel-vbtn.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/intel-vbtn.c b/drivers/platform/x86/intel-vbtn.c
index e42203776727..23cda7aa96cd 100644
--- a/drivers/platform/x86/intel-vbtn.c
+++ b/drivers/platform/x86/intel-vbtn.c
@@ -54,6 +54,7 @@ static const struct key_entry intel_vbtn_switchmap[] = {
struct intel_vbtn_priv {
struct key_entry keymap[KEYMAP_LEN];
struct input_dev *input_dev;
+ bool has_switches;
bool wakeup_mode;
};

@@ -69,7 +70,7 @@ static int intel_vbtn_input_setup(struct platform_device *device)
keymap_len += ARRAY_SIZE(intel_vbtn_keymap);
}

- if (true) {
+ if (priv->has_switches) {
memcpy(&priv->keymap[keymap_len], intel_vbtn_switchmap,
ARRAY_SIZE(intel_vbtn_switchmap) *
sizeof(struct key_entry));
@@ -137,16 +138,12 @@ out_unknown:

static void detect_tablet_mode(struct platform_device *device)
{
- const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
acpi_handle handle = ACPI_HANDLE(&device->dev);
unsigned long long vgbs;
acpi_status status;
int m;

- if (!(chassis_type && strcmp(chassis_type, "31") == 0))
- return;
-
status = acpi_evaluate_integer(handle, "VGBS", NULL, &vgbs);
if (ACPI_FAILURE(status))
return;
@@ -157,6 +154,19 @@ static void detect_tablet_mode(struct platform_device *device)
input_report_switch(priv->input_dev, SW_DOCK, m);
}

+static bool intel_vbtn_has_switches(acpi_handle handle)
+{
+ const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
+ unsigned long long vgbs;
+ acpi_status status;
+
+ if (!(chassis_type && strcmp(chassis_type, "31") == 0))
+ return false;
+
+ status = acpi_evaluate_integer(handle, "VGBS", NULL, &vgbs);
+ return ACPI_SUCCESS(status);
+}
+
static int intel_vbtn_probe(struct platform_device *device)
{
acpi_handle handle = ACPI_HANDLE(&device->dev);
@@ -175,13 +185,16 @@ static int intel_vbtn_probe(struct platform_device *device)
return -ENOMEM;
dev_set_drvdata(&device->dev, priv);

+ priv->has_switches = intel_vbtn_has_switches(handle);
+
err = intel_vbtn_input_setup(device);
if (err) {
pr_err("Failed to setup Intel Virtual Button\n");
return err;
}

- detect_tablet_mode(device);
+ if (priv->has_switches)
+ detect_tablet_mode(device);

status = acpi_install_notify_handler(handle,
ACPI_DEVICE_NOTIFY,
--
2.25.1