bcm27xx: sync 5.4 patches with RPi Foundation

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.4/950-0281-drm-vc4-A-present-but-empty-dmas-disables-audio.patch b/target/linux/bcm27xx/patches-5.4/950-0281-drm-vc4-A-present-but-empty-dmas-disables-audio.patch
new file mode 100644
index 0000000000..84b044eb63
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.4/950-0281-drm-vc4-A-present-but-empty-dmas-disables-audio.patch
@@ -0,0 +1,33 @@
+From 88d5709082671ff2abeddc2a9b4acacbb85b9194 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Wed, 31 Jul 2019 17:36:34 +0100
+Subject: [PATCH] drm/vc4: A present but empty dmas disables audio
+
+Overlays are unable to remove properties in the base DTB, but they
+can overwrite them. Allow a present but empty 'dmas' property
+to also disable the HDMI audio interface.
+
+See: https://github.com/raspberrypi/linux/issues/2489
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.org>
+---
+ drivers/gpu/drm/vc4/vc4_hdmi.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
++++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
+@@ -1054,10 +1054,12 @@ static int vc4_hdmi_audio_init(struct vc
+ 	struct device *dev = &hdmi->pdev->dev;
+ 	const __be32 *addr;
+ 	int ret;
++	int len;
+ 
+-	if (!of_find_property(dev->of_node, "dmas", NULL)) {
++	if (!of_find_property(dev->of_node, "dmas", &len) ||
++	    len == 0) {
+ 		dev_warn(dev,
+-			 "'dmas' DT property is missing, no HDMI audio\n");
++			 "'dmas' DT property is missing or empty, no HDMI audio\n");
+ 		return 0;
+ 	}
+