linux-libre-rt-3.4.4_rt13-1: updating version

1 files changed, 38 insertions, 0 deletions

diff --git a/kernels/linux-libre-rt/3.4.4-fix-backlight-regression.patch b/kernels/linux-libre-rt/3.4.4-fix-backlight-regression.patch
new file mode 100644
index 000000000..a0cf0b1db
--- /dev/null
+++ b/kernels/linux-libre-rt/3.4.4-fix-backlight-regression.patch
@@ -0,0 +1,38 @@
+Subject: Still use ACPI backlight control if _DOS doesn't exist
+
+This is a regression introduced by commit
+ea9f8856bd6d4ed45885b06a338f7362cd6c60e5
+
+https://bugzilla.kernel.org/show_bug.cgi?id=43168
+
+Some platforms don't have _DOS control method, but the ACPI
+backlight still works.
+We do not want to lose the backlight control ability on these platforms.
+
+CC : Igor Murzov <intergalactic.anonymous@gmail.com>
+Signed-off-by: Zhang Rui <rui.zhang@intel.com>
+---
+ drivers/acpi/video.c |   10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+Index: rtd3/drivers/acpi/video.c
+===================================================================
+--- rtd3.orig/drivers/acpi/video.c
++++ rtd3/drivers/acpi/video.c
+@@ -565,8 +565,14 @@ acpi_video_bus_DOS(struct acpi_video_bus
+ 	video->dos_setting = arg0.integer.value;
+ 	status = acpi_evaluate_object(video->device->handle, "_DOS",
+ 		&args, NULL);
+-	if (ACPI_FAILURE(status))
+-		return -EIO;
++	if (ACPI_FAILURE(status)) {
++		/*
++		 * some platforms don't have _DOS, but the ACPI
++		 * backlight control still works
++		 */
++		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _DOS\n"));
++		return 0;
++	}
+ 
+ 	return 0;
+ }