This is a note to let you know that I've just added the patch titled
ACPI: video: Allow GPU drivers to report no panels
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
acpi-video-allow-gpu-drivers-to-report-no-panels.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7339ac100c3f74369c99b51c04cc0b7f63f80da5
Author: Mario Limonciello <mario.limonciello@xxxxxxx>
Date: Thu Dec 8 10:42:05 2022 -0600
ACPI: video: Allow GPU drivers to report no panels
[ Upstream commit 00a734104af7d878f1252d49eff9298785c6cbdc ]
The current logic for the ACPI backlight detection will create
a backlight device if no native or vendor drivers have created
8 seconds after the system has booted if the ACPI tables
included backlight control methods.
If the GPU drivers have loaded, they may be able to report whether
any LCD panels were found. Allow using this information to factor
in whether to enable the fallback logic for making an acpi_video0
backlight device.
Suggested-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index 32953646caeb..f64fdb029090 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -2178,6 +2178,17 @@ static bool should_check_lcd_flag(void)
return false;
}
+/*
+ * At least one graphics driver has reported that no LCD is connected
+ * via the native interface. cancel the registration for fallback acpi_video0.
+ * If another driver still deems this necessary, it can explicitly register it.
+ */
+void acpi_video_report_nolcd(void)
+{
+ cancel_delayed_work(&video_bus_register_backlight_work);
+}
+EXPORT_SYMBOL(acpi_video_report_nolcd);
+
int acpi_video_register(void)
{
int ret = 0;
diff --git a/include/acpi/video.h b/include/acpi/video.h
index a275c35e5249..8ed9bec03e53 100644
--- a/include/acpi/video.h
+++ b/include/acpi/video.h
@@ -53,6 +53,7 @@ enum acpi_backlight_type {
};
#if IS_ENABLED(CONFIG_ACPI_VIDEO)
+extern void acpi_video_report_nolcd(void);
extern int acpi_video_register(void);
extern void acpi_video_unregister(void);
extern void acpi_video_register_backlight(void);
@@ -69,6 +70,7 @@ extern int acpi_video_get_levels(struct acpi_device *device,
struct acpi_video_device_brightness **dev_br,
int *pmax_level);
#else
+static inline void acpi_video_report_nolcd(void) { return; };
static inline int acpi_video_register(void) { return -ENODEV; }
static inline void acpi_video_unregister(void) { return; }
static inline void acpi_video_register_backlight(void) { return; }
