[PATCH 3.16 95/99] ALSA: hda/tegra: clear pending irq handlers

[Ben Hutchings]

3.16.65-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Sameer Pujar <spujar@xxxxxxxxxx>

commit 63d2a9ec310d8bcc955574220d4631aa55c1a80c upstream.

Even after disabling interrupts on the module, it could be possible
that irq handlers are still running. System hang is seen during
suspend path. It was found that, there were pending writes on the
HDA bus and clock was disabled by that time.

Above mentioned issue is fixed by clearing any pending irq handlers
before disabling clocks and returning from hda suspend.

Suggested-by: Mohan Kumar <mkumard@xxxxxxxxxx>
Suggested-by: Dara Ramesh <dramesh@xxxxxxxxxx>
Signed-off-by: Sameer Pujar <spujar@xxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 sound/pci/hda/hda_tegra.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/sound/pci/hda/hda_tegra.c
+++ b/sound/pci/hda/hda_tegra.c
@@ -253,6 +253,7 @@ static int hda_tegra_suspend(struct devi
 	struct azx *chip = card->private_data;
 	struct azx_pcm *p;
 	struct hda_tegra *hda = container_of(chip, struct hda_tegra, chip);
+	struct hdac_bus *bus = azx_bus(chip);
 
 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
 	list_for_each_entry(p, &chip->pcm_list, list)
@@ -261,6 +262,7 @@ static int hda_tegra_suspend(struct devi
 		snd_hda_suspend(chip->bus);
 
 	azx_stop_chip(chip);
+	synchronize_irq(bus->irq);
 	azx_enter_link_reset(chip);
 	hda_tegra_disable_clocks(hda);