From fedbe9bc6fd3e14b1ffbb3dac407777ac4a3650c Mon Sep 17 00:00:00 2001
From: Alex Hung <alex.hung@canonical.com>
Date: Tue, 28 May 2013 02:05:09 +0000
Subject: [PATCH] ACPI / video: ignore BIOS initial backlight value for HP m4

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
Cc: All <stable@vger.kernel.org>
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/video.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 5b32e15a65ce..d0937ab3fb6d 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -464,6 +464,14 @@ 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"),
+		},
+	},
 	{}
 };
 
-- 
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