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 91357e1a1a882783adbd0a201ace6d17251509d0..753b766208f88191291b3980f1f7b2f9aaf33d2d 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"),
+               },
+       },
        {}
 };