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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 313f959413dc09a89c8a8262957b35081b1e2b0b..80938cb7d0d4f505957fc136d7356c857206737c 100644 (file)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -447,6 +447,14 @@ 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 m4",
+        .matches = {
+               DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
+               DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion m4 Notebook PC"),
+               },
+       },
        {}
 };