linux-kernel - [PATCH] PM: sleep: core: Resume suspended device if direct-complete is disabled

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Date:   Thu, 31 Dec 2020 14:03:19 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     rjw@...ysocki.net
Cc:     tiwai@...e.de, kenny@...ix.com,
        Kai-Heng Feng <kai.heng.feng@...onical.com>,
        Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-pm@...r.kernel.org (open list:HIBERNATION (aka Software Suspend,
        aka swsusp)), linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] PM: sleep: core: Resume suspended device if direct-complete is disabled

HDA controller can't be runtime-suspended after commit 215a22ed31a1
("ALSA: hda: Refactor codjc PM to use direct-complete optimization"),
which enables direct-complete for HDA codec.

The HDA codec driver doesn't expect direct-complete will be disabled
after it returns a positive value from prepare() callback. So freeze()
is called directly when it's runtime-suspended, breaks the balance of
its internal codec_powered counting.

So if a device is prepared for direct-complete but PM core breaks the
assumption, resume the device to keep PM operations balanced.

Fixes: 215a22ed31a1 ("ALSA: hda: Refactor codec PM to use direct-complete optimization")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
---
 drivers/base/power/main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 46793276598d..9c0e25a92ad0 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1849,6 +1849,10 @@ static int device_prepare(struct device *dev, pm_message_t state)
 		(ret > 0 || dev->power.no_pm_callbacks) &&
 		!dev_pm_test_driver_flags(dev, DPM_FLAG_NO_DIRECT_COMPLETE);
 	spin_unlock_irq(&dev->power.lock);
+
+	if (ret > 0 && !dev->power.direct_complete)
+		pm_runtime_resume(dev);
+
 	return 0;
 }
 
-- 
2.29.2