@@ -26,6 +26,7 @@
*/
#include <linux/acpi.h>
+#include <linux/backlight.h>
#include <linux/dmi.h>
#include <linux/firmware.h>
#include <acpi/video.h>
@@ -467,7 +468,7 @@ static u32 asle_set_backlight(struct drm_i915_private *dev_priv, u32 bclp)
drm_dbg(&dev_priv->drm, "bclp = 0x%08x\n", bclp);
- if (acpi_video_get_backlight_type() == acpi_backlight_native) {
+ if (!backlight_device_non_raw_exists()) {
drm_dbg_kms(&dev_priv->drm,
"opregion backlight request ignored\n");
return 0;
@@ -516,6 +516,24 @@ struct backlight_device *backlight_device_get_by_name(const char *name)
}
EXPORT_SYMBOL(backlight_device_get_by_name);
+bool backlight_device_non_raw_exists(void)
+{
+ bool found = false;
+ struct backlight_device *bd;
+
+ mutex_lock(&backlight_dev_list_mutex);
+ list_for_each_entry(bd, &backlight_dev_list, entry) {
+ if (bd->props.type != BACKLIGHT_RAW) {
+ found = true;
+ break;
+ }
+ }
+ mutex_unlock(&backlight_dev_list_mutex);
+
+ return found;
+}
+EXPORT_SYMBOL(backlight_device_non_raw_exists);
+
/* deprecated - use devm_backlight_device_unregister() */
void backlight_device_unregister(struct backlight_device *bd)
{
@@ -444,6 +444,7 @@ int backlight_register_notifier(struct notifier_block *nb);
int backlight_unregister_notifier(struct notifier_block *nb);
struct backlight_device *backlight_device_get_by_name(const char *name);
struct backlight_device *backlight_device_get_by_type(enum backlight_type type);
+bool backlight_device_non_raw_exists(void);
int backlight_device_set_brightness(struct backlight_device *bd,
unsigned long brightness);
asle_set_backlight() needs to accept backlight request only if the firmware controls the backlight. It used the following expression for this purpose: acpi_video_get_backlight_type() == acpi_backlight_native This expression works well in practice, but has two semantic problems. One is that it actually determines if a backlight device which directly modifies hardware registers ("native backlight") exists. It is possible that a device which does not have backlight at all incorrectly triggers asle_set_backlight(), and the expression does not cover such a case. Another problem is that acpi_video_get_backlight_type() always return acpi_backlight_vendor in reality if CONFIG_ACPI_VIDEO is unset. It means even its ability to determine the existence of native backlight is somewhat limited. This change introduces a new function backlight_device_non_raw_exists(), which returns if the firmware is controlling the backlight, and is always available if backlight support is enabled. Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> --- drivers/gpu/drm/i915/display/intel_opregion.c | 3 ++- drivers/video/backlight/backlight.c | 18 ++++++++++++++++++ include/linux/backlight.h | 1 + 3 files changed, 21 insertions(+), 1 deletion(-)