[3.11.y.z extended stable] Patch "drm/radeon: set default bl level to something reasonable" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    drm/radeon: set default bl level to something reasonable

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 7b2bac060c2d0055522d8716ea9cb1df866a1bd1 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher at amd.com>
Date: Tue, 15 Jul 2014 09:48:53 -0400
Subject: drm/radeon: set default bl level to something reasonable

commit 201bb62402e0227375c655446ea04fcd0acf7287 upstream.

If the value in the scratch register is 0, set it to the
max level.  This fixes an issue where the console fb blanking
code calls back into the backlight driver on unblank and then
sets the backlight level to 0 after the driver has already
set the mode and enabled the backlight.

bugs:
https://bugs.freedesktop.org/show_bug.cgi?id=81382
https://bugs.freedesktop.org/show_bug.cgi?id=70207

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Tested-by: David Heidelberger <david.heidelberger at ixit.cz>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/radeon/atombios_encoders.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index 76e5e29ac46c..af359bae3e6f 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -183,7 +183,6 @@ void radeon_atom_backlight_init(struct radeon_encoder *radeon_encoder,
 	struct backlight_properties props;
 	struct radeon_backlight_privdata *pdata;
 	struct radeon_encoder_atom_dig *dig;
-	u8 backlight_level;
 	char bl_name[16];

 	/* Mac laptops with multiple GPUs use the gmux driver for backlight
@@ -222,12 +221,17 @@ void radeon_atom_backlight_init(struct radeon_encoder *radeon_encoder,

 	pdata->encoder = radeon_encoder;

-	backlight_level = radeon_atom_get_backlight_level_from_reg(rdev);
-
 	dig = radeon_encoder->enc_priv;
 	dig->bl_dev = bd;

 	bd->props.brightness = radeon_atom_backlight_get_brightness(bd);
+	/* Set a reasonable default here if the level is 0 otherwise
+	 * fbdev will attempt to turn the backlight on after console
+	 * unblanking and it will try and restore 0 which turns the backlight
+	 * off again.
+	 */
+	if (bd->props.brightness == 0)
+		bd->props.brightness = RADEON_MAX_BL_LEVEL;
 	bd->props.power = FB_BLANK_UNBLANK;
 	backlight_update_status(bd);

--
1.9.1