linux-kernel - [PATCH v1 2/2] media: hi846: preserve the streaming state during system suspend

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Message-Id: <20230405092904.1129395-3-martin.kepplinger@puri.sm>
Date:   Wed,  5 Apr 2023 11:29:04 +0200
From:   Martin Kepplinger <martin.kepplinger@...i.sm>
To:     mchehab@...nel.org, laurent.pinchart@...asonboard.com
Cc:     kernel@...i.sm, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Martin Kepplinger <martin.kepplinger@...i.sm>
Subject: [PATCH v1 2/2] media: hi846: preserve the streaming state during system suspend

The hi846 driver changed the "streaming" state inside of "start/stop_streaming".
The problem is that inside of the (system) suspend callback, it calls
"stop_streaming" unconditionally. So streaming would always be stopped
when suspending.

That makes sense with runtime pm for example, after s_stream(..., 0) but
does not preserve the "streaming" state during system suspend when
currently streaming.

Fix this by simply setting the streaming state outside of "start/stop_streaming"
which is s_stream().

While at it, improve things a bit by not assigning "1", but the "enable"
value we later compare against, and fix one error handling path in resume().

Signed-off-by: Martin Kepplinger <martin.kepplinger@...i.sm>
---
 drivers/media/i2c/hi846.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/media/i2c/hi846.c b/drivers/media/i2c/hi846.c
index 0b0eda2e223cd..1ca6e9407d618 100644
--- a/drivers/media/i2c/hi846.c
+++ b/drivers/media/i2c/hi846.c
@@ -1780,8 +1780,6 @@ static int hi846_start_streaming(struct hi846 *hi846)
 		return ret;
 	}
 
-	hi846->streaming = 1;
-
 	dev_dbg(&client->dev, "%s: started streaming successfully\n", __func__);
 
 	return ret;
@@ -1793,8 +1791,6 @@ static void hi846_stop_streaming(struct hi846 *hi846)
 
 	if (hi846_write_reg(hi846, HI846_REG_MODE_SELECT, HI846_MODE_STANDBY))
 		dev_err(&client->dev, "failed to stop stream");
-
-	hi846->streaming = 0;
 }
 
 static int hi846_set_stream(struct v4l2_subdev *sd, int enable)
@@ -1816,10 +1812,12 @@ static int hi846_set_stream(struct v4l2_subdev *sd, int enable)
 		}
 
 		ret = hi846_start_streaming(hi846);
+		hi846->streaming = enable;
 	}
 
 	if (!enable || ret) {
 		hi846_stop_streaming(hi846);
+		hi846->streaming = 0;
 		pm_runtime_put(&client->dev);
 	}
 
@@ -1898,6 +1896,8 @@ static int __maybe_unused hi846_resume(struct device *dev)
 		if (ret) {
 			dev_err(dev, "%s: start streaming failed: %d\n",
 				__func__, ret);
+			hi846_stop_streaming(hi846);
+			hi846->streaming = 0;
 			goto error;
 		}
 	}
-- 
2.30.2