[systemd-devel] [PATCH 2/3] rules: Enable runtime device power management on a subset of HDA codecs

[Matthew Garrett]

From: Matthew Garrett <mjg59 at coreos.com>

4.1 ports HDA codec power management to the standard runtime PM framework,
which means we have per-codec control over whether it's enabled or not.
We've traditionally left this disabled because on some codecs enabling it
causes popping noises on power transitions, but now we can whitelist on a
per-codec basis. This patch simply enables it for the Broadwell HDMI codec
with the aim that we can add more based on user feedback.
---
 Makefile.am                 | 3 ++-
 rules/90-hda-codec-pm.rules | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 rules/90-hda-codec-pm.rules

diff --git a/Makefile.am b/Makefile.am
index d23c428..40cf101 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -3753,7 +3753,8 @@ dist_udevrules_DATA += \
 	rules/75-net-description.rules \
 	rules/78-sound-card.rules \
 	rules/80-net-setup-link.rules \
-	rules/90-hda-controller-pm.rules
+	rules/90-hda-controller-pm.rules \
+	rules/90-hda-codec-pm.rules
 
 nodist_udevrules_DATA += \
 	rules/99-systemd.rules
diff --git a/rules/90-hda-codec-pm.rules b/rules/90-hda-codec-pm.rules
new file mode 100644
index 0000000..e0c55e1
--- /dev/null
+++ b/rules/90-hda-codec-pm.rules
@@ -0,0 +1,4 @@
+# Enable autosuspend for some HDA codecs 
+
+ACTION=="add", SUBSYSTEM=="hdaudio", ATTR{chip_name}=="Broadwell HDMI", ATTR{power/control}="auto"
+
-- 
2.3.5