@@ -9086,6 +9086,14 @@ void intel_display_driver_register(struct drm_i915_private *i915)
/* Must be done after probing outputs */
intel_opregion_register(i915);
acpi_video_register();
+ /*
+ * Only call this if i915 is driving the internal panel. If the internal
+ * panel is not driven by i915 then another GPU driver may still register
+ * a native backlight driver later and this should only be called after
+ * any native backlights have been registered.
+ */
+ if (i915->have_panel)
+ acpi_video_register_backlight();
intel_audio_init(i915);
@@ -646,8 +646,11 @@ intel_panel_mode_valid(struct intel_connector *connector,
int intel_panel_init(struct intel_connector *connector)
{
+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
struct intel_panel *panel = &connector->panel;
+ dev_priv->have_panel = true;
+
intel_backlight_init_funcs(panel);
drm_dbg_kms(connector->base.dev,
@@ -756,6 +756,8 @@ struct drm_i915_private {
bool ipc_enabled;
+ bool have_panel;
+
struct intel_audio_private audio;
struct i915_pmu pmu;
On machins without an i915 opregion the acpi_video driver immediately probes the ACPI video bus and used to also immediately register acpi_video# backlight devices when supported. Once the drm/kms driver then loaded later and possibly registered a native backlight device then the drivers/acpi/video_detect.c code unregistered the acpi_video0 device to avoid there being 2 backlight devices (when acpi_video_get_backlight_type()==native). This means that userspace used to briefly see 2 devices and the disappearing of acpi_video0 after a brief time confuses the systemd backlight level save/restore code, see e.g.: https://bbs.archlinux.org/viewtopic.php?id=269920 To fix this the ACPI video code has been modified to make backlight class device registration a separate step, relying on the drm/kms driver to ask for the acpi_video backlight registration after it is done setting up its native backlight device. Add a call to the new acpi_video_register_backlight() after the i915 calls acpi_video_register() (after setting up the i915 opregion) so that the acpi_video backlight devices get registered on systems where the i915 native backlight device is not registered. Changes in v2: -Only call acpi_video_register_backlight() when a panel is detected Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- drivers/gpu/drm/i915/display/intel_display.c | 8 ++++++++ drivers/gpu/drm/i915/display/intel_panel.c | 3 +++ drivers/gpu/drm/i915/i915_drv.h | 2 ++ 3 files changed, 13 insertions(+)