Patch "toshiba_acpi: Fix blank screen at boot if transflective backlight is supported" has been added to the 4.4-stable tree

Patch "toshiba_acpi: Fix blank screen at boot if transflective backlight is supported" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    toshiba_acpi: Fix blank screen at boot if transflective backlight is supported

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     toshiba_acpi-fix-blank-screen-at-boot-if-transflective-backlight-is-supported.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From bae5336f0aaedffa115dab9cb3d8a4e4aed3a26a Mon Sep 17 00:00:00 2001
From: Azael Avalos <coproscefalo@gmail.com>
Date: Sun, 15 Nov 2015 20:32:47 -0700
Subject: toshiba_acpi: Fix blank screen at boot if transflective backlight is supported

From: Azael Avalos <coproscefalo@gmail.com>

commit bae5336f0aaedffa115dab9cb3d8a4e4aed3a26a upstream.

If transflective backlight is supported and the brightness is zero
(lowest brightness level), the set_lcd_brightness function will activate
the transflective backlight, making the LCD appear to be turned off.

This patch fixes the issue by incrementing the brightness level, and
by doing so, avoiding the activation of the tranflective backlight.

Reported-and-tested-by: Fabian Koester <fabian.koester@bringnow.com>
Signed-off-by: Azael Avalos <coproscefalo@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/platform/x86/toshiba_acpi.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/platform/x86/toshiba_acpi.c
+++ b/drivers/platform/x86/toshiba_acpi.c
@@ -2484,6 +2484,14 @@ static int toshiba_acpi_setup_backlight(
 	brightness = __get_lcd_brightness(dev);
 	if (brightness < 0)
 		return 0;
+	/*
+	 * If transflective backlight is supported and the brightness is zero
+	 * (lowest brightness level), the set_lcd_brightness function will
+	 * activate the transflective backlight, making the LCD appear to be
+	 * turned off, simply increment the brightness level to avoid that.
+	 */
+	if (dev->tr_backlight_supported && brightness == 0)
+		brightness++;
 	ret = set_lcd_brightness(dev, brightness);
 	if (ret) {
 		pr_debug("Backlight method is read-only, disabling backlight support\n");


Patches currently in stable-queue which might be from coproscefalo@gmail.com are

queue-4.4/toshiba_acpi-fix-blank-screen-at-boot-if-transflective-backlight-is-supported.patch