ACPI video: ignore BIOS backlight value for HP dm4

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>

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 4d608fccee1eb2e1f4dc1dfaff61f3d498e9e721..8c5ad89a65a5c8c79cc75abab2c97a68e3fdaf93 100644 (file)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -471,6 +471,14 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
                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"),
+               },
+       },
        {}
 };