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authorHans de Goede <hdegoede@redhat.com>2022-12-15 12:41:38 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-12-22 19:36:49 +0300
commit3cf3b7f012f3ea8bdc56196e367cf07c10424855 (patch)
tree28dc75d25e3240b81eab583aa60566b8a6fda3ee /drivers/acpi
parent5aa9d943e9b6bf6e6023645cbe7ce7d5ed84baf4 (diff)
downloadlinux-3cf3b7f012f3ea8bdc56196e367cf07c10424855.tar.xz
ACPI: video: Fix Apple GMUX backlight detection
The apple-gmux driver only binds to old GMUX devices which have an IORESOURCE_IO resource (using inb()/outb()) rather then memory-mapped IO (IORESOURCE_MEM). T2 MacBooks use the new style GMUX devices (with IORESOURCE_MEM access), so these are not supported by the apple-gmux driver. This is not a problem since they have working ACPI video backlight support. But the apple_gmux_present() helper only checks if an ACPI device with the "APP000B" HID is present, causing acpi_video_get_backlight_type() to return acpi_backlight_apple_gmux disabling the acpi_video backlight device. Add a new apple_gmux_backlight_present() helper which checks that the "APP000B" device actually is an old GMUX device with an IORESOURCE_IO resource. This fixes the acpi_video0 backlight no longer registering on T2 MacBooks. Note people are working to add support for the new style GMUX to Linux: https://github.com/kekrby/linux-t2/commits/wip/hybrid-graphics Once this lands this patch should be reverted so that acpi_video_get_backlight_type() also prefers the gmux on new style GMUX MacBooks, but for now this is necessary to avoid regressing backlight control on T2 Macs. Fixes: 21245df307cb ("ACPI: video: Add Apple GMUX brightness control detection") Reported-and-tested-by: Aditya Garg <gargaditya08@live.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/video_detect.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index a934bbc9dd37..1b78c7434492 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -34,6 +34,7 @@
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_data/x86/nvidia-wmi-ec-backlight.h>
+#include <linux/pnp.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <acpi/video.h>
@@ -105,6 +106,26 @@ static bool nvidia_wmi_ec_supported(void)
}
#endif
+static bool apple_gmux_backlight_present(void)
+{
+ struct acpi_device *adev;
+ struct device *dev;
+
+ adev = acpi_dev_get_first_match_dev(GMUX_ACPI_HID, NULL, -1);
+ if (!adev)
+ return false;
+
+ dev = acpi_get_first_physical_node(adev);
+ if (!dev)
+ return false;
+
+ /*
+ * drivers/platform/x86/apple-gmux.c only supports old style
+ * Apple GMUX with an IO-resource.
+ */
+ return pnp_get_resource(to_pnp_dev(dev), IORESOURCE_IO, 0) != NULL;
+}
+
/* Force to use vendor driver when the ACPI device is known to be
* buggy */
static int video_detect_force_vendor(const struct dmi_system_id *d)
@@ -767,7 +788,7 @@ static enum acpi_backlight_type __acpi_video_get_backlight_type(bool native)
if (nvidia_wmi_ec_present)
return acpi_backlight_nvidia_wmi_ec;
- if (apple_gmux_present())
+ if (apple_gmux_backlight_present())
return acpi_backlight_apple_gmux;
/* Use ACPI video if available, except when native should be preferred. */