ACPI / video: ignore BIOS initial backlight value for HP m4

commit fedbe9bc6fd3e14b1ffbb3dac407777ac4a3650c upstream.

On HP m4 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References: https://bugs.launchpad.net/bugs/1184501
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 464daf8cffbefef5a1149172066b292fd7a789eb..3451dbd14abc8980bfeac2e6cf2a3c902edd6cda 100644 (file)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -463,6 +463,14 @@ 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 m4",
+        .matches = {
+               DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion m4 Notebook PC"),
+               },
+       },
        {}
 };