When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
with the above config, backlight support is disabled.
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Reported-by: Martin Liška <mliska@xxxxxxx>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
index beba39a38c87..c1ba68796b6d 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
mutex_unlock(&dev_priv->display.backlight.lock);
}
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
static u32 intel_panel_get_backlight(struct intel_connector *connector)
{
struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
index 339643f63897..207fe1c613d8 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.h
+++ b/drivers/gpu/drm/i915/display/intel_backlight.h
@@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
int intel_backlight_device_register(struct intel_connector *connector);
void intel_backlight_device_unregister(struct intel_connector *connector);
#else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
--
2.37.3
