This is a note to let you know that I've just added the patch titled drm/i915: Fix runtime PM for LPE audio to the 4.11-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: drm-i915-fix-runtime-pm-for-lpe-audio.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 668e3b014afb66ab29e134bca7c258527273ac75 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@xxxxxxxxxxxxxxx> Date: Thu, 27 Apr 2017 19:02:20 +0300 Subject: drm/i915: Fix runtime PM for LPE audio MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> commit 668e3b014afb66ab29e134bca7c258527273ac75 upstream. Not calling pm_runtime_enable() means that runtime PM can't be enabled at all via sysfs. So we definitely need to call it from somewhere. Calling it from the driver seems like a bad idea because it would have to be paired with a pm_runtime_disable() at driver unload time, otherwise the core gets upset. Also if there's no LPE audio driver loaded then we couldn't runtime suspend i915 either. So it looks like a better plan is to call it from i915 when we register the platform device. That seems to match how pci generally does things. I cargo culted the pm_runtime_forbid() and pm_runtime_set_active() calls from pci as well. The exposed runtime PM API is massive an thorougly misleading, so I don't actually know if this is how you're supposed to use the API or not. But it seems to work. I can now runtime suspend i915 again with or without the LPE audio driver loaded, and reloading the LPE audio driver also seems to work. Note that powertop won't auto-tune runtime PM for platform devices, which is a little annoying. So I'm not sure that leaving runtime PM in "on" mode by default is the best choice here. But I've left it like that for now at least. Also remove the comment about there not being much benefit from LPE audio runtime PM. Not allowing runtime PM blocks i915 runtime PM, which will also block s0ix, and that could have a measurable impact on power consumption. Cc: Takashi Iwai <tiwai@xxxxxxx> Cc: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> Fixes: 0b6b524f3915 ("ALSA: x86: Don't enable runtime PM as default") Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Link: http://patchwork.freedesktop.org/patch/msgid/20170427160231.13337-2-ville.syrjala@xxxxxxxxxxxxxxx Reviewed-by: Takashi Iwai <tiwai@xxxxxxx> (cherry picked from commit 183c00350ccda86781f6695840e6c5f5b22efbd1) Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_lpe_audio.c | 5 +++++ sound/x86/intel_hdmi_audio.c | 4 ---- 2 files changed, 5 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/i915/intel_lpe_audio.c +++ b/drivers/gpu/drm/i915/intel_lpe_audio.c @@ -63,6 +63,7 @@ #include <linux/acpi.h> #include <linux/device.h> #include <linux/pci.h> +#include <linux/pm_runtime.h> #include "i915_drv.h" #include <linux/delay.h> @@ -121,6 +122,10 @@ lpe_audio_platdev_create(struct drm_i915 kfree(rsc); + pm_runtime_forbid(&platdev->dev); + pm_runtime_set_active(&platdev->dev); + pm_runtime_enable(&platdev->dev); + return platdev; err: --- a/sound/x86/intel_hdmi_audio.c +++ b/sound/x86/intel_hdmi_audio.c @@ -1809,10 +1809,6 @@ static int hdmi_lpe_audio_probe(struct p pdata->notify_pending = false; spin_unlock_irq(&pdata->lpe_audio_slock); - /* runtime PM isn't enabled as default, since it won't save much on - * BYT/CHT devices; user who want the runtime PM should adjust the - * power/ontrol and power/autosuspend_delay_ms sysfs entries instead - */ pm_runtime_use_autosuspend(&pdev->dev); pm_runtime_mark_last_busy(&pdev->dev); pm_runtime_set_active(&pdev->dev); Patches currently in stable-queue which might be from ville.syrjala@xxxxxxxxxxxxxxx are queue-4.11/drm-i915-fix-runtime-pm-for-lpe-audio.patch