[PATCH 1/2] ACPI video: ignore BIOS backlight value for HP dm4

[Alex Hung]

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

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 at sagui.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
(cherry picked from commit 771d09b3c4c45d4d534a83a68e6331b97fd82e15)

Signed-off-by: Alex Hung <alex.hung at canonical.com>
---
 drivers/acpi/video.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 7025e48..584f7b5 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -455,6 +455,14 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13 - 2000 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"),
+		},
+	},
 	{}
 };
 
-- 
1.7.9.5