ALSA: hda - Manage power well properly for resume

For SKL and later Intel chips, we control the power well per codec
basis via link_power callback since the commit [03b135cebc47: ALSA:
hda - remove dependency on i915 power well for SKL].
However, there are a few exceptional cases where the gfx registers are
accessed from the audio driver: namely the wakeup override bit
toggling at (both system and runtime) resume.  This seems causing a
kernel warning when accessed during the power well down (and likely
resulting in the bogus register accesses).

This patch puts the proper power up / down sequence around the resume
code so that the wakeup bit is fiddled properly while the power is
up.  (The other callback, sync_audio_rate, is used only in the PCM
callback, so it's guaranteed in the power-on.)

Also, by this proper power up/down, the instantaneous flip of wakeup
bit in the resume callback that was introduced by the commit
[033ea349a7cd: ALSA: hda - Fix Skylake codec timeout] becomes
superfluous, as snd_hdac_display_power() already does it.  So we can
clean it up together.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96214
Fixes: 03b135cebc47 ('ALSA: hda - remove dependency on i915 power well for SKL')
Cc: <stable@vger.kernel.org> # v4.2+
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 20 insertions, 12 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 89dacf9b4e6c..160c7f713722 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -906,20 +906,23 @@ static int azx_resume(struct device *dev)
         struct snd_card *card = dev_get_drvdata(dev);
         struct azx *chip;
         struct hda_intel *hda;
+        struct hdac_bus *bus;
 
         if (!card)
                 return 0;
 
         chip = card->private_data;
         hda = container_of(chip, struct hda_intel, chip);
+        bus = azx_bus(chip);
         if (chip->disabled || hda->init_failed || !chip->running)
                 return 0;
 
-        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL
-                && hda->need_i915_power) {
-                snd_hdac_display_power(azx_bus(chip), true);
-                snd_hdac_i915_set_bclk(azx_bus(chip));
+        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) {
+                snd_hdac_display_power(bus, true);
+                if (hda->need_i915_power)
+                        snd_hdac_i915_set_bclk(bus);
         }
+
         if (chip->msi)
                 if (pci_enable_msi(pci) < 0)
                         chip->msi = 0;
@@ -929,6 +932,11 @@ static int azx_resume(struct device *dev)
 
         hda_intel_init_chip(chip, true);
 
+        /* power down again for link-controlled chips */
+        if ((chip->driver_caps & AZX_DCAPS_I915_POWERWELL) &&
+            !hda->need_i915_power)
+                snd_hdac_display_power(bus, false);
+
         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
 
         trace_azx_resume(chip);
@@ -1008,6 +1016,7 @@ static int azx_runtime_resume(struct device *dev)
 
         chip = card->private_data;
         hda = container_of(chip, struct hda_intel, chip);
+        bus = azx_bus(chip);
         if (chip->disabled || hda->init_failed)
                 return 0;
 
@@ -1015,15 +1024,9 @@ static int azx_runtime_resume(struct device *dev)
                 return 0;
 
         if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) {
-                bus = azx_bus(chip);
-                if (hda->need_i915_power) {
-                        snd_hdac_display_power(bus, true);
+                snd_hdac_display_power(bus, true);
+                if (hda->need_i915_power)
                         snd_hdac_i915_set_bclk(bus);
-                } else {
-                        /* toggle codec wakeup bit for STATESTS read */
-                        snd_hdac_set_codec_wakeup(bus, true);
-                        snd_hdac_set_codec_wakeup(bus, false);
-                }
         }
 
         /* Read STATESTS before controller reset */
@@ -1043,6 +1046,11 @@ static int azx_runtime_resume(struct device *dev)
         azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) &
                         ~STATESTS_INT_MASK);
 
+        /* power down again for link-controlled chips */
+        if ((chip->driver_caps & AZX_DCAPS_I915_POWERWELL) &&
+            !hda->need_i915_power)
+                snd_hdac_display_power(bus, false);
+
         trace_azx_runtime_resume(chip);
         return 0;
 }