ALSA: hda - Handle pm failure during hotplug

Obtaining the runtime pm wakeref can fail, especially in a hotplug
scenario where i915.ko has been unloaded. If we do not catch the
failure, we end up with an unbalanced pm.

v2 additions by tiwai:
hdmi_present_sense() checks the return value and handle only a
negative error case and bails out only if it's really still suspended.
Also, snd_hda_power_down() is called at the error path so that the
refcount is balanced.

Along with it, the spec->pcm_lock is taken outside
hdmi_present_sense() in the caller side, so that it won't cause
deadlock at reentrace via runtime resume.

v3 fix by tiwai:
Missing linux/pm_runtime.h is included.

References: 222bde03881c ("ALSA: hda - Fix mutex deadlock at HDMI/DP hotplug")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 98e1c411c56abbd36bcd18d1c13fa27f2826bad2..8a49415aebacb79cd3da6b90b1a34e041da02bbd 100644 (file)
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -33,6 +33,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 #include <sound/core.h>
 #include <sound/jack.h>
 #include <sound/asoundef.h>
@@ -764,8 +765,10 @@ static void check_presence_and_report(struct hda_codec *codec, hda_nid_t nid,
 
        if (pin_idx < 0)
                return;
+       mutex_lock(&spec->pcm_lock);
        if (hdmi_present_sense(get_pin(spec, pin_idx), 1))
                snd_hda_jack_report_sync(codec);
+       mutex_unlock(&spec->pcm_lock);
 }
 
 static void jack_callback(struct hda_codec *codec,
@@ -1628,21 +1631,23 @@ static void sync_eld_via_acomp(struct hda_codec *codec,
 static bool hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
 {
        struct hda_codec *codec = per_pin->codec;
-       struct hdmi_spec *spec = codec->spec;
        int ret;
 
        /* no temporary power up/down needed for component notifier */
-       if (!codec_has_acomp(codec))
-               snd_hda_power_up_pm(codec);
+       if (!codec_has_acomp(codec)) {
+               ret = snd_hda_power_up_pm(codec);
+               if (ret < 0 && pm_runtime_suspended(hda_codec_dev(codec))) {
+                       snd_hda_power_down_pm(codec);
+                       return false;
+               }
+       }
 
-       mutex_lock(&spec->pcm_lock);
        if (codec_has_acomp(codec)) {
                sync_eld_via_acomp(codec, per_pin);
                ret = false; /* don't call snd_hda_jack_report_sync() */
        } else {
                ret = hdmi_present_sense_via_verbs(per_pin, repoll);
        }
-       mutex_unlock(&spec->pcm_lock);
 
        if (!codec_has_acomp(codec))
                snd_hda_power_down_pm(codec);
@@ -1654,12 +1659,16 @@ static void hdmi_repoll_eld(struct work_struct *work)
 {
        struct hdmi_spec_per_pin *per_pin =
        container_of(to_delayed_work(work), struct hdmi_spec_per_pin, work);
+       struct hda_codec *codec = per_pin->codec;
+       struct hdmi_spec *spec = codec->spec;
 
        if (per_pin->repoll_count++ > 6)
                per_pin->repoll_count = 0;
 
+       mutex_lock(&spec->pcm_lock);
        if (hdmi_present_sense(per_pin, per_pin->repoll_count))
                snd_hda_jack_report_sync(per_pin->codec);
+       mutex_unlock(&spec->pcm_lock);
 }
 
 static void intel_haswell_fixup_connect_list(struct hda_codec *codec,