[PATCH 3.4 43/44] ACPI video: ignore BIOS backlight value for HP dm4

Greg Kroah-Hartman
2014-07-08T00:03:45Z

From: Gustavo Maciel Dias Vieira <gustavo@sagui.org>

commit 771d09b3c4c45d4d534a83a68e6331b97fd82e15 upstream.

On a HP Pavilion dm4 laptop the BIOS sets minimum backlight on boot,
completely dimming the screen. Ignore this initial value for this
machine.

Signed-off-by: Gustavo Maciel Dias Vieira <gustavo@sagui.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[wyj: Backported to 3.4: adjust context]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/acpi/video.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -471,6 +471,14 @@ static struct dmi_system_id video_dmi_ta
DMI_MATCH(DMI_PRODUCT_NAME, "HP 1000 Notebook PC"),
},
},
+ {
+ .callback = video_ignore_initial_backlight,
+ .ident = "HP Pavilion dm4",
+ .matches = {
+ DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dm4 Notebook PC"),
+ },
+ },
{}
};