kernel/samsung-laptop-brightness-fixes-3.2.patch

From: Jason Stubbs <jasonbstubbs@gmail.com>
Date: Tue, 20 Sep 2011 16:16:13 +0000 (-0700)
Subject: Platform: Brightness quirk for samsung laptop driver
X-Git-Tag: v3.2-rc1~111^2~41
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=ac080523141d5bfa5f60ef2436480f645f915e9c

Platform: Brightness quirk for samsung laptop driver

On some Samsung laptops the brightness regulation works slightly different.
All SABI commands except for set_brightness work as expected. The behaviour
of set_brightness is as follows:

- Setting a new brightness will only step one level toward the new brightness
  level. For example, setting a level of 5 when the current level is 2 will
  result in a brightness level of 3.
- A spurious KEY_BRIGHTNESS_UP or KEY_BRIGHTNESS_DOWN event is also generated
  along with the change in brightness.
- Neither of the above two issues occur when changing from/to brightness
  level 0.

This patch adds detection and a non-intrusive workaround for the above issues.

Signed-off-by: Jason Stubbs <jasonbstubbs@gmail.com>
Tested-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
---

diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index 4d3bed4..6474e42 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -226,6 +226,7 @@ static struct backlight_device *backlight_device;
 static struct mutex sabi_mutex;
 static struct platform_device *sdev;
 static struct rfkill *rfk;
+static bool has_stepping_quirk;
 
 static int force;
 module_param(force, bool, 0);
@@ -382,6 +383,17 @@ static void set_brightness(u8 user_brightness)
 {
 	u8 user_level = user_brightness + sabi_config->min_brightness;
 
+	if (has_stepping_quirk && user_level != 0) {
+		/*
+		 * short circuit if the specified level is what's already set
+		 * to prevent the screen from flickering needlessly
+		 */
+		if (user_brightness == read_brightness())
+			return;
+
+		sabi_set_command(sabi_config->commands.set_brightness, 0);
+	}
+
 	sabi_set_command(sabi_config->commands.set_brightness, user_level);
 }
 
@@ -390,6 +402,34 @@ static int get_brightness(struct backlight_device *bd)
 	return (int)read_brightness();
 }
 
+static void check_for_stepping_quirk(void)
+{
+	u8 initial_level = read_brightness();
+	u8 check_level;
+
+	/*
+	 * Some laptops exhibit the strange behaviour of stepping toward
+	 * (rather than setting) the brightness except when changing to/from
+	 * brightness level 0. This behaviour is checked for here and worked
+	 * around in set_brightness.
+	 */
+
+	if (initial_level <= 2)
+		check_level = initial_level + 2;
+	else
+		check_level = initial_level - 2;
+
+	has_stepping_quirk = false;
+	set_brightness(check_level);
+
+	if (read_brightness() != check_level) {
+		has_stepping_quirk = true;
+		pr_info("enabled workaround for brightness stepping quirk\n");
+	}
+
+	set_brightness(initial_level);
+}
+
 static int update_status(struct backlight_device *bd)
 {
 	set_brightness(bd->props.brightness);
@@ -805,6 +845,9 @@ static int __init samsung_init(void)
 		}
 	}
 
+	/* Check for stepping quirk */
+	check_for_stepping_quirk();
+
 	/* knock up a platform device to hang stuff off of */
 	sdev = platform_device_register_simple("samsung", -1, NULL, 0);
 	if (IS_ERR(sdev))
From: Jason Stubbs <jasonbstubbs@gmail.com>
Date: Tue, 20 Sep 2011 16:16:14 +0000 (-0700)
Subject: Platform: Samsung laptop DMI info for NC210/NC110
X-Git-Tag: v3.2-rc1~111^2~40
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=7b3c257ce4267e004a7c7e68c05d1eb70da8c972

Platform: Samsung laptop DMI info for NC210/NC110

This patch just adds the DMI info for the samsung laptop driver to work with
the NC210/NC110. It needs the brightness quirk patch for proper support.

Signed-off-by: Jason Stubbs <jasonbstubbs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
---

diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index 6474e42..8ffab50 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -737,6 +737,15 @@ static struct dmi_system_id __initdata samsung_dmi_table[] = {
 		},
 		.callback = dmi_check_cb,
 	},
+	{
+		.ident = "NC210/NC110",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "NC210/NC110"),
+			DMI_MATCH(DMI_BOARD_NAME, "NC210/NC110"),
+		},
+		.callback = dmi_check_cb,
+	},
 	{ },
 };
 MODULE_DEVICE_TABLE(dmi, samsung_dmi_table);
From: Raul Gutierrez Segales <rgs@collabora.co.uk>
Date: Tue, 20 Sep 2011 16:16:15 +0000 (-0700)
Subject: Platform: fix samsung-laptop DMI identification for N220 model
X-Git-Tag: v3.2-rc1~111^2~39
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=f689c875c13c9d62b3c4de09cd5dad66549f700d

Platform: fix samsung-laptop DMI identification for N220 model

This is a follow-up for commit 78a7539b, which didn't cover the
Samsung N220 laptop. With this backlight brightness works nicely
on the N220 netbook.

Signed-off-by: Raul Gutierrez Segales <rgs@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
---

diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index 8ffab50..1e436eb 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -663,6 +663,16 @@ static struct dmi_system_id __initdata samsung_dmi_table[] = {
 		.callback = dmi_check_cb,
 	},
 	{
+		.ident = "N220",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR,
+					"SAMSUNG ELECTRONICS CO., LTD."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "N220"),
+			DMI_MATCH(DMI_BOARD_NAME, "N220"),
+		},
+		.callback = dmi_check_cb,
+	},
+	{
 		.ident = "N150/N210/N220/N230",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR,
From: John Serock <john.serock@gmail.com>
Date: Thu, 13 Oct 2011 10:42:01 +0000 (-0400)
Subject: Platform: Detect samsung laptop quirk when initial level is zero
X-Git-Tag: v3.2-rc1~111^2~29
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=ba05b237372bad82533d1f717569d1d817ff3c27

Platform: Detect samsung laptop quirk when initial level is zero

This patch depends on the "Platform: Brightness quirk for samsung
laptop driver" patch from Jason Stubbs. This patch adds a check for an
initial brightness level of 0; if the level is 0, this patch changes
the brightness level to 1 before the driver attempts to detect the
brightness quirk.

The Samsung N150 netbook experiences the brightness quirk. Without
Jason's patch, the only brightness levels available on the N150 are 0,
1, and 8. This patch ensures that, when the initial brightness level
is 0, the samsang-laptop driver detects the brightness quirk on the
N150, thereby making brightness levels 0 through 8 available.

Signed-off-by: John Serock <john.serock@gmail.com>
Acked-by: Jason Stubbs <jasonbstubbs@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
---

diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index 1e436eb..31ddd57 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -404,8 +404,9 @@ static int get_brightness(struct backlight_device *bd)
 
 static void check_for_stepping_quirk(void)
 {
-	u8 initial_level = read_brightness();
+	u8 initial_level;
 	u8 check_level;
+	u8 orig_level = read_brightness();
 
 	/*
 	 * Some laptops exhibit the strange behaviour of stepping toward
@@ -414,6 +415,11 @@ static void check_for_stepping_quirk(void)
 	 * around in set_brightness.
 	 */
 
+	if (orig_level == 0)
+		set_brightness(1);
+
+	initial_level = read_brightness();
+
 	if (initial_level <= 2)
 		check_level = initial_level + 2;
 	else
@@ -427,7 +433,7 @@ static void check_for_stepping_quirk(void)
 		pr_info("enabled workaround for brightness stepping quirk\n");
 	}
 
-	set_brightness(initial_level);
+	set_brightness(orig_level);
 }
 
 static int update_status(struct backlight_device *bd)