4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Azael Avalos <[email protected]> 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 <[email protected]> Signed-off-by: Azael Avalos <[email protected]> Signed-off-by: Darren Hart <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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");
