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-rw-r--r--drivers/acpi/video.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index cd4fb7543a9..7e8ee49ebd4 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -538,6 +538,33 @@ acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
return -EINVAL;
}
+/*
+ * For some buggy _BQC methods, we need to add a constant value to
+ * the _BQC return value to get the actual current brightness level
+ */
+
+static int bqc_offset_aml_bug_workaround;
+static int __init video_set_bqc_offset(const struct dmi_system_id *d)
+{
+ bqc_offset_aml_bug_workaround = 9;
+ return 0;
+}
+
+static struct dmi_system_id video_dmi_table[] __initdata = {
+ /*
+ * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
+ */
+ {
+ .callback = video_set_bqc_offset,
+ .ident = "Acer Aspire 5720",
+ .matches = {
+ DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
+ },
+ },
+ {}
+};
+
static int
acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
unsigned long long *level)
@@ -557,6 +584,7 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
*level = device->brightness->levels[*level + 2];
}
+ *level += bqc_offset_aml_bug_workaround;
device->brightness->curr = *level;
return 0;
} else {
@@ -2287,6 +2315,8 @@ EXPORT_SYMBOL(acpi_video_register);
static int __init acpi_video_init(void)
{
+ dmi_check_system(video_dmi_table);
+
if (intel_opregion_present())
return 0;