On Fri, Aug 06, 2021 at 08:07:08AM -0700, psodagud@codeaurora.org wrote:

On 2021-08-03 10:16, Greg KH wrote:

quoted

On Mon, Jul 26, 2021 at 08:24:34AM -0700, Prasad Sodagudi wrote:

quoted

There are variables(power.may_skip_resume and dev->power.must_resume)
and DPM_FLAG_MAY_SKIP_RESUME flags to control the resume of devices
after
a system wide suspend transition.

Setting the DPM_FLAG_MAY_SKIP_RESUME flag means that the driver allows
its "noirq" and "early" resume callbacks to be skipped if the device
can be left in suspend after a system-wide transition into the working
state. PM core determines that the driver's "noirq" and "early" resume
callbacks should be skipped or not with dev_pm_skip_resume()
function by
checking power.may_skip_resume variable.

power.must_resume variable is getting set to false in
__device_suspend()
function without checking device's DPM_FLAG_MAY_SKIP_RESUME and
dev->power.usage_count variables. This is leading to failure to call
resume handler for some of the devices suspended in early suspend
phase.
So check device's DPM_FLAG_MAY_SKIP_RESUME flag before
setting power.must_resume variable.

Signed-off-by: Prasad Sodagudi <redacted>
---
 drivers/base/power/main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index d568772..8eebc4d 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c

@@ -1642,7 +1642,11 @@ static int __device_suspend(struct device

*dev, pm_message_t state, bool async)
 	}

 	dev->power.may_skip_resume = true;
-	dev->power.must_resume = false;
+	if ((atomic_read(&dev->power.usage_count) <= 1) &&
+			(dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME)))

What is preventing that atomic value from changing _right_ after you
just read this?

and very odd indentation, checkpatch didn't complain about this?

Sure. I will fix indentation problem once Rafael reviewed this patch.

Neither of us can take this as-is, so why wait?