[PATCH v3 0/1] media: atomisp: mt9m114: graceful teardown and reprobe fixes

[PATCH v3 0/1] media: atomisp: mt9m114: graceful teardown and reprobe fixes

[Robert Mast]

Hi,

this series addresses unload/reload instability between atomisp and mt9m114
seen on ACPI Bay Trail systems.

Problem summary:
- notifier lifecycle in atomisp could leave stale async state behind,
  breaking subsequent probe/reprobe cycles
- mt9m114 remove path could race async unregister callback ordering
- reprobe after module cycling could fail or crash around endpoint/clock setup

This patch hardens teardown/probe behavior by:
- explicitly unregistering and cleaning atomisp async notifier state
- synchronizing mt9m114 async unregister via completion
- adding safer remove/shutdown handling in mt9m114
- making link-frequency control/validation robust when frequencies are absent
- using safe fallback clocking in the ACPI no-link-frequency path

Observed result on the test platform:
- repeated modprobe -r/modprobe cycles are stable
- no probe oops during the tested unload/reload loops

Changes in v3:
- clarify commit message around teardown/reprobe failure modes
- keep atomisp notifier cleanup in both normal teardown and parse error paths
- keep mt9m114 fallback clocking in the no-link-frequency ACPI path
- refresh cover letter with tested behavior summary

Changes in v2:
- initial split and hardening for atomisp notifier + mt9m114 teardown paths

Robert Mast (1):
  media: atomisp: mt9m114: Graceful teardown atomisp and mt9m114

 drivers/media/i2c/mt9m114.c                   | 118 ++++++++++++++++--
 .../media/atomisp/pci/atomisp_csi2_bridge.c   |   1 +
 .../staging/media/atomisp/pci/atomisp_v4l2.c  |   3 +
 3 files changed, 110 insertions(+), 12 deletions(-)

-- 
2.53.0

[PATCH v3 1/1] media: atomisp: mt9m114: graceful teardown and reprobe fixes

[Robert Mast]

Repeated modprobe -r/modprobe cycles of atomisp and mt9m114 could leave
stale async state behind and trigger unstable reprobe behavior on ACPI
Bay Trail systems.

The failure modes observed during stress loops included notifier lifecycle
issues during atomisp teardown, ordering races between mt9m114 async
unregister callback and remove cleanup, and unreliable probe behavior when
endpoint link-frequency data is unavailable.

Harden both drivers by:
- explicitly unregistering and cleaning atomisp async notifier state in
	normal teardown and CSI2 parse error paths
- synchronizing mt9m114 remove with async-unregister completion before
	tearing down dependent subdev state
- adding a shutdown callback to ensure stream/power state is clean at
	shutdown/reboot
- guarding LINK_FREQ control creation and validating parsed frequency menus
- using default PLL clocking when no link-frequencies are available,
	instead of taking an unsuitable bypass path

This makes unload/reload cycles stable and avoids the reprobe failures that
were seen after repeated module teardown.

Signed-off-by: Robert Mast <rn.mast@zonnet.nl>
---
 drivers/media/i2c/mt9m114.c                   | 118 ++++++++++++++++--
 .../media/atomisp/pci/atomisp_csi2_bridge.c   |   1 +
 .../staging/media/atomisp/pci/atomisp_v4l2.c  |   3 +
 3 files changed, 110 insertions(+), 12 deletions(-)

diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
index 16b0ace15813..27432a9c683d 100644
--- a/drivers/media/i2c/mt9m114.c
+++ b/drivers/media/i2c/mt9m114.c
@@ -10,6 +10,8 @@
  */
 
 #include <linux/clk.h>
+#include <linux/acpi.h>
+#include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/gpio/consumer.h>
@@ -416,6 +418,7 @@ struct mt9m114 {
 		unsigned int frame_rate;
 
 		struct v4l2_ctrl *tpg[4];
+		struct completion unregistered;
 	} ifp;
 };
 
@@ -1467,6 +1470,8 @@ static int mt9m114_pa_init(struct mt9m114 *sensor)
 
 	sd->ctrl_handler = hdl;
 
+	init_completion(&sensor->ifp.unregistered);
+
 	return 0;
 
 error:
@@ -2056,8 +2061,13 @@ static int mt9m114_ifp_set_selection(struct v4l2_subdev *sd,
 static void mt9m114_ifp_unregistered(struct v4l2_subdev *sd)
 {
 	struct mt9m114 *sensor = ifp_to_mt9m114(sd);
+	struct device *dev = &sensor->client->dev;
+
+	dev_dbg(dev, "ifp unregistered callback (ifp.v4l2_dev=%p, pa.v4l2_dev=%p)\n",
+		sensor->ifp.sd.v4l2_dev, sensor->pa.sd.v4l2_dev);
 
 	v4l2_device_unregister_subdev(&sensor->pa.sd);
+	complete(&sensor->ifp.unregistered);
 }
 
 static int mt9m114_ifp_registered(struct v4l2_subdev *sd)
@@ -2149,12 +2159,15 @@ static int mt9m114_ifp_init(struct mt9m114 *sensor)
 			       V4L2_EXPOSURE_MANUAL, 0,
 			       V4L2_EXPOSURE_AUTO);
 
-	link_freq = v4l2_ctrl_new_int_menu(hdl, &mt9m114_ifp_ctrl_ops,
-					   V4L2_CID_LINK_FREQ,
-					   sensor->bus_cfg.nr_of_link_frequencies - 1,
-					   0, sensor->bus_cfg.link_frequencies);
-	if (link_freq)
-		link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+	if (sensor->bus_cfg.nr_of_link_frequencies) {
+		link_freq = v4l2_ctrl_new_int_menu(hdl, &mt9m114_ifp_ctrl_ops,
+						   V4L2_CID_LINK_FREQ,
+						   sensor->bus_cfg.nr_of_link_frequencies - 1,
+						   0,
+						   sensor->bus_cfg.link_frequencies);
+		if (link_freq)
+			link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+	}
 
 	v4l2_ctrl_new_std(hdl, &mt9m114_ifp_ctrl_ops,
 			  V4L2_CID_PIXEL_RATE,
@@ -2339,14 +2352,19 @@ static const struct dev_pm_ops mt9m114_pm_ops = {
 static int mt9m114_verify_link_frequency(struct mt9m114 *sensor,
 					 unsigned int pixrate)
 {
+	u32 i;
 	unsigned int link_freq = sensor->bus_cfg.bus_type == V4L2_MBUS_CSI2_DPHY
 			       ? pixrate * 8 : pixrate * 2;
 
-	if (sensor->bus_cfg.nr_of_link_frequencies != 1 ||
-	    sensor->bus_cfg.link_frequencies[0] != link_freq)
+	if (!sensor->bus_cfg.nr_of_link_frequencies)
 		return -EINVAL;
 
-	return 0;
+	for (i = 0; i < sensor->bus_cfg.nr_of_link_frequencies; i++) {
+		if (sensor->bus_cfg.link_frequencies[i] == link_freq)
+			return 0;
+	}
+
+	return -EINVAL;
 }
 
 /*
@@ -2383,6 +2401,29 @@ static int mt9m114_clk_init(struct mt9m114 *sensor)
 	unsigned int pixrate;
 	int ret;
 
+	if (!sensor->bus_cfg.nr_of_link_frequencies) {
+		/*
+		 * ACPI fallback path: no reliable endpoint link frequency available.
+		 * Use the default PLL target instead of EXTCLK bypass to avoid
+		 * under-clocking the sensor and getting blank/timeout streams.
+		 */
+		sensor->pll.ext_clock = clk_get_rate(sensor->clk);
+		sensor->pll.pix_clock = MT9M114_DEF_PIXCLOCK;
+
+		ret = aptina_pll_calculate(&sensor->client->dev, &limits,
+					  &sensor->pll);
+		if (ret)
+			return ret;
+
+		sensor->pixrate = sensor->pll.ext_clock * sensor->pll.m
+			/ (sensor->pll.n * sensor->pll.p1);
+		sensor->bypass_pll = false;
+
+		dev_warn(&sensor->client->dev,
+			 "no link-frequencies provided, using default PLL clocking\n");
+		return 0;
+	}
+
 	/*
 	 * Calculate the pixel rate and link frequency. The CSI-2 bus is clocked
 	 * for 16-bit per pixel, transmitted in DDR over a single lane. For
@@ -2456,10 +2497,25 @@ static int mt9m114_identify(struct mt9m114 *sensor)
 
 static int mt9m114_parse_dt(struct mt9m114 *sensor)
 {
-	struct fwnode_handle *fwnode = dev_fwnode(&sensor->client->dev);
+	struct fwnode_handle *fwnode;
 	struct fwnode_handle *ep;
 	int ret;
 
+#if IS_ENABLED(CONFIG_ACPI)
+	if (has_acpi_companion(&sensor->client->dev)) {
+		/*
+		 * On some reload sequences a stale software-node graph can be
+		 * observed for this ACPI-enumerated sensor. Use the known safe
+		 * default bus configuration and skip endpoint graph parsing.
+		 */
+		memset(&sensor->bus_cfg, 0, sizeof(sensor->bus_cfg));
+		sensor->bus_cfg.bus_type = V4L2_MBUS_CSI2_DPHY;
+		sensor->bus_cfg.bus.mipi_csi2.num_data_lanes = 1;
+		goto read_slew_rate;
+	}
+#endif
+	fwnode = dev_fwnode(&sensor->client->dev);
+
 	/*
 	 * On ACPI systems the fwnode graph can be initialized by a bridge
 	 * driver, which may not have probed yet. Wait for this.
@@ -2468,6 +2524,9 @@ static int mt9m114_parse_dt(struct mt9m114 *sensor)
 	 * to the ACPI core.
 	 */
 	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
+	if (IS_ERR(ep))
+		return dev_err_probe(&sensor->client->dev, PTR_ERR(ep),
+				     "failed to get fwnode graph endpoint\n");
 	if (!ep)
 		return dev_err_probe(&sensor->client->dev, -EPROBE_DEFER,
 				     "waiting for fwnode graph endpoint\n");
@@ -2492,6 +2551,7 @@ static int mt9m114_parse_dt(struct mt9m114 *sensor)
 		goto error;
 	}
 
+read_slew_rate:
 	sensor->pad_slew_rate = MT9M114_PAD_SLEW_DEFAULT;
 	device_property_read_u32(&sensor->client->dev, "slew-rate",
 				 &sensor->pad_slew_rate);
@@ -2629,8 +2689,22 @@ static void mt9m114_remove(struct i2c_client *client)
 	struct v4l2_subdev *sd = i2c_get_clientdata(client);
 	struct mt9m114 *sensor = ifp_to_mt9m114(sd);
 	struct device *dev = &client->dev;
-
-	v4l2_async_unregister_subdev(&sensor->ifp.sd);
+	bool ifp_async_registered = sensor->ifp.sd.async_list.next;
+	bool ifp_bound = sensor->ifp.sd.v4l2_dev;
+
+	dev_dbg(dev,
+		"remove start (ifp_bound=%u ifp_async_registered=%u ifp.v4l2_dev=%p pa.v4l2_dev=%p)\n",
+		ifp_bound, ifp_async_registered,
+		sensor->ifp.sd.v4l2_dev, sensor->pa.sd.v4l2_dev);
+
+	if (ifp_async_registered) {
+		reinit_completion(&sensor->ifp.unregistered);
+		v4l2_async_unregister_subdev(&sensor->ifp.sd);
+		if (ifp_bound)
+			wait_for_completion(&sensor->ifp.unregistered);
+	} else {
+		dev_warn(dev, "ifp async subdev already unregistered, skipping\n");
+	}
 
 	mt9m114_ifp_cleanup(sensor);
 	mt9m114_pa_cleanup(sensor);
@@ -2646,6 +2720,25 @@ static void mt9m114_remove(struct i2c_client *client)
 	pm_runtime_set_suspended(dev);
 }
 
+static void mt9m114_shutdown(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct mt9m114 *sensor;
+
+	if (!sd)
+		return;
+
+	sensor = ifp_to_mt9m114(sd);
+
+	if (sensor->streaming)
+		mt9m114_stop_streaming(sensor);
+
+	pm_runtime_disable(&client->dev);
+	if (!pm_runtime_status_suspended(&client->dev))
+		mt9m114_power_off(sensor);
+	pm_runtime_set_suspended(&client->dev);
+}
+
 static const struct of_device_id mt9m114_of_ids[] = {
 	{ .compatible = "onnn,mt9m114" },
 	{ /* sentinel */ },
@@ -2667,6 +2760,7 @@ static struct i2c_driver mt9m114_driver = {
 	},
 	.probe		= mt9m114_probe,
 	.remove		= mt9m114_remove,
+	.shutdown	= mt9m114_shutdown,
 };
 
 module_i2c_driver(mt9m114_driver);
diff --git a/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c b/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c
index 2a90f86e515f..87f8ddcd6651 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c
@@ -547,6 +547,7 @@ int atomisp_csi2_bridge_parse_firmware(struct atomisp_device *isp)
 
 err_parse:
 		fwnode_handle_put(ep);
+		v4l2_async_nf_cleanup(&isp->notifier);
 		return ret;
 	}
 
diff --git a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
index 900a67552d6a..32a1f85ab598 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
@@ -805,6 +805,9 @@ static void atomisp_unregister_entities(struct atomisp_device *isp)
 	unsigned int i;
 	struct v4l2_subdev *sd, *next;
 
+	v4l2_async_nf_unregister(&isp->notifier);
+	v4l2_async_nf_cleanup(&isp->notifier);
+
 	atomisp_subdev_unregister_entities(&isp->asd);
 	for (i = 0; i < ATOMISP_CAMERA_NR_PORTS; i++)
 		atomisp_mipi_csi2_unregister_entities(&isp->csi2_port[i]);
-- 
2.53.0

Re: [PATCH v3 1/1] media: atomisp: mt9m114: graceful teardown and reprobe fixes

[Laurent Pinchart]

On Sun, Apr 19, 2026 at 05:25:14PM +0200, Robert Mast wrote:
> Repeated modprobe -r/modprobe cycles of atomisp and mt9m114 could leave
> stale async state behind and trigger unstable reprobe behavior on ACPI
> Bay Trail systems.
> 
> The failure modes observed during stress loops included notifier lifecycle
> issues during atomisp teardown, ordering races between mt9m114 async
> unregister callback and remove cleanup, and unreliable probe behavior when
> endpoint link-frequency data is unavailable.
> 
> Harden both drivers by:
> - explicitly unregistering and cleaning atomisp async notifier state in
> 	normal teardown and CSI2 parse error paths
> - synchronizing mt9m114 remove with async-unregister completion before
> 	tearing down dependent subdev state
> - adding a shutdown callback to ensure stream/power state is clean at
> 	shutdown/reboot
> - guarding LINK_FREQ control creation and validating parsed frequency menus
> - using default PLL clocking when no link-frequencies are available,
> 	instead of taking an unsuitable bypass path
> 
> This makes unload/reload cycles stable and avoids the reprobe failures that
> were seen after repeated module teardown.

As I mentioned in a review of a previous version, please stop dumping
LLM-generated code on the list. You need to understand what you're
doing, and to put the hours of work required to produce acceptable
patches.

A good starting point will be to read the kernel development
documentation, in particular the patch submission guidelines.

> Signed-off-by: Robert Mast <rn.mast@zonnet.nl>
> ---
>  drivers/media/i2c/mt9m114.c                   | 118 ++++++++++++++++--
>  .../media/atomisp/pci/atomisp_csi2_bridge.c   |   1 +
>  .../staging/media/atomisp/pci/atomisp_v4l2.c  |   3 +
>  3 files changed, 110 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
> index 16b0ace15813..27432a9c683d 100644
> --- a/drivers/media/i2c/mt9m114.c
> +++ b/drivers/media/i2c/mt9m114.c
> @@ -10,6 +10,8 @@
>   */
>  
>  #include <linux/clk.h>
> +#include <linux/acpi.h>
> +#include <linux/completion.h>
>  #include <linux/delay.h>
>  #include <linux/errno.h>
>  #include <linux/gpio/consumer.h>
> @@ -416,6 +418,7 @@ struct mt9m114 {
>  		unsigned int frame_rate;
>  
>  		struct v4l2_ctrl *tpg[4];
> +		struct completion unregistered;
>  	} ifp;
>  };
>  
> @@ -1467,6 +1470,8 @@ static int mt9m114_pa_init(struct mt9m114 *sensor)
>  
>  	sd->ctrl_handler = hdl;
>  
> +	init_completion(&sensor->ifp.unregistered);
> +
>  	return 0;
>  
>  error:
> @@ -2056,8 +2061,13 @@ static int mt9m114_ifp_set_selection(struct v4l2_subdev *sd,
>  static void mt9m114_ifp_unregistered(struct v4l2_subdev *sd)
>  {
>  	struct mt9m114 *sensor = ifp_to_mt9m114(sd);
> +	struct device *dev = &sensor->client->dev;
> +
> +	dev_dbg(dev, "ifp unregistered callback (ifp.v4l2_dev=%p, pa.v4l2_dev=%p)\n",
> +		sensor->ifp.sd.v4l2_dev, sensor->pa.sd.v4l2_dev);
>  
>  	v4l2_device_unregister_subdev(&sensor->pa.sd);
> +	complete(&sensor->ifp.unregistered);
>  }
>  
>  static int mt9m114_ifp_registered(struct v4l2_subdev *sd)
> @@ -2149,12 +2159,15 @@ static int mt9m114_ifp_init(struct mt9m114 *sensor)
>  			       V4L2_EXPOSURE_MANUAL, 0,
>  			       V4L2_EXPOSURE_AUTO);
>  
> -	link_freq = v4l2_ctrl_new_int_menu(hdl, &mt9m114_ifp_ctrl_ops,
> -					   V4L2_CID_LINK_FREQ,
> -					   sensor->bus_cfg.nr_of_link_frequencies - 1,
> -					   0, sensor->bus_cfg.link_frequencies);
> -	if (link_freq)
> -		link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +	if (sensor->bus_cfg.nr_of_link_frequencies) {
> +		link_freq = v4l2_ctrl_new_int_menu(hdl, &mt9m114_ifp_ctrl_ops,
> +						   V4L2_CID_LINK_FREQ,
> +						   sensor->bus_cfg.nr_of_link_frequencies - 1,
> +						   0,
> +						   sensor->bus_cfg.link_frequencies);
> +		if (link_freq)
> +			link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +	}
>  
>  	v4l2_ctrl_new_std(hdl, &mt9m114_ifp_ctrl_ops,
>  			  V4L2_CID_PIXEL_RATE,
> @@ -2339,14 +2352,19 @@ static const struct dev_pm_ops mt9m114_pm_ops = {
>  static int mt9m114_verify_link_frequency(struct mt9m114 *sensor,
>  					 unsigned int pixrate)
>  {
> +	u32 i;
>  	unsigned int link_freq = sensor->bus_cfg.bus_type == V4L2_MBUS_CSI2_DPHY
>  			       ? pixrate * 8 : pixrate * 2;
>  
> -	if (sensor->bus_cfg.nr_of_link_frequencies != 1 ||
> -	    sensor->bus_cfg.link_frequencies[0] != link_freq)
> +	if (!sensor->bus_cfg.nr_of_link_frequencies)
>  		return -EINVAL;
>  
> -	return 0;
> +	for (i = 0; i < sensor->bus_cfg.nr_of_link_frequencies; i++) {
> +		if (sensor->bus_cfg.link_frequencies[i] == link_freq)
> +			return 0;
> +	}
> +
> +	return -EINVAL;
>  }
>  
>  /*
> @@ -2383,6 +2401,29 @@ static int mt9m114_clk_init(struct mt9m114 *sensor)
>  	unsigned int pixrate;
>  	int ret;
>  
> +	if (!sensor->bus_cfg.nr_of_link_frequencies) {
> +		/*
> +		 * ACPI fallback path: no reliable endpoint link frequency available.
> +		 * Use the default PLL target instead of EXTCLK bypass to avoid
> +		 * under-clocking the sensor and getting blank/timeout streams.
> +		 */
> +		sensor->pll.ext_clock = clk_get_rate(sensor->clk);
> +		sensor->pll.pix_clock = MT9M114_DEF_PIXCLOCK;
> +
> +		ret = aptina_pll_calculate(&sensor->client->dev, &limits,
> +					  &sensor->pll);
> +		if (ret)
> +			return ret;
> +
> +		sensor->pixrate = sensor->pll.ext_clock * sensor->pll.m
> +			/ (sensor->pll.n * sensor->pll.p1);
> +		sensor->bypass_pll = false;
> +
> +		dev_warn(&sensor->client->dev,
> +			 "no link-frequencies provided, using default PLL clocking\n");
> +		return 0;
> +	}
> +
>  	/*
>  	 * Calculate the pixel rate and link frequency. The CSI-2 bus is clocked
>  	 * for 16-bit per pixel, transmitted in DDR over a single lane. For
> @@ -2456,10 +2497,25 @@ static int mt9m114_identify(struct mt9m114 *sensor)
>  
>  static int mt9m114_parse_dt(struct mt9m114 *sensor)
>  {
> -	struct fwnode_handle *fwnode = dev_fwnode(&sensor->client->dev);
> +	struct fwnode_handle *fwnode;
>  	struct fwnode_handle *ep;
>  	int ret;
>  
> +#if IS_ENABLED(CONFIG_ACPI)
> +	if (has_acpi_companion(&sensor->client->dev)) {
> +		/*
> +		 * On some reload sequences a stale software-node graph can be
> +		 * observed for this ACPI-enumerated sensor. Use the known safe
> +		 * default bus configuration and skip endpoint graph parsing.
> +		 */
> +		memset(&sensor->bus_cfg, 0, sizeof(sensor->bus_cfg));
> +		sensor->bus_cfg.bus_type = V4L2_MBUS_CSI2_DPHY;
> +		sensor->bus_cfg.bus.mipi_csi2.num_data_lanes = 1;
> +		goto read_slew_rate;
> +	}
> +#endif
> +	fwnode = dev_fwnode(&sensor->client->dev);
> +
>  	/*
>  	 * On ACPI systems the fwnode graph can be initialized by a bridge
>  	 * driver, which may not have probed yet. Wait for this.
> @@ -2468,6 +2524,9 @@ static int mt9m114_parse_dt(struct mt9m114 *sensor)
>  	 * to the ACPI core.
>  	 */
>  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> +	if (IS_ERR(ep))
> +		return dev_err_probe(&sensor->client->dev, PTR_ERR(ep),
> +				     "failed to get fwnode graph endpoint\n");
>  	if (!ep)
>  		return dev_err_probe(&sensor->client->dev, -EPROBE_DEFER,
>  				     "waiting for fwnode graph endpoint\n");
> @@ -2492,6 +2551,7 @@ static int mt9m114_parse_dt(struct mt9m114 *sensor)
>  		goto error;
>  	}
>  
> +read_slew_rate:
>  	sensor->pad_slew_rate = MT9M114_PAD_SLEW_DEFAULT;
>  	device_property_read_u32(&sensor->client->dev, "slew-rate",
>  				 &sensor->pad_slew_rate);
> @@ -2629,8 +2689,22 @@ static void mt9m114_remove(struct i2c_client *client)
>  	struct v4l2_subdev *sd = i2c_get_clientdata(client);
>  	struct mt9m114 *sensor = ifp_to_mt9m114(sd);
>  	struct device *dev = &client->dev;
> -
> -	v4l2_async_unregister_subdev(&sensor->ifp.sd);
> +	bool ifp_async_registered = sensor->ifp.sd.async_list.next;
> +	bool ifp_bound = sensor->ifp.sd.v4l2_dev;
> +
> +	dev_dbg(dev,
> +		"remove start (ifp_bound=%u ifp_async_registered=%u ifp.v4l2_dev=%p pa.v4l2_dev=%p)\n",
> +		ifp_bound, ifp_async_registered,
> +		sensor->ifp.sd.v4l2_dev, sensor->pa.sd.v4l2_dev);
> +
> +	if (ifp_async_registered) {
> +		reinit_completion(&sensor->ifp.unregistered);
> +		v4l2_async_unregister_subdev(&sensor->ifp.sd);
> +		if (ifp_bound)
> +			wait_for_completion(&sensor->ifp.unregistered);
> +	} else {
> +		dev_warn(dev, "ifp async subdev already unregistered, skipping\n");
> +	}
>  
>  	mt9m114_ifp_cleanup(sensor);
>  	mt9m114_pa_cleanup(sensor);
> @@ -2646,6 +2720,25 @@ static void mt9m114_remove(struct i2c_client *client)
>  	pm_runtime_set_suspended(dev);
>  }
>  
> +static void mt9m114_shutdown(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct mt9m114 *sensor;
> +
> +	if (!sd)
> +		return;
> +
> +	sensor = ifp_to_mt9m114(sd);
> +
> +	if (sensor->streaming)
> +		mt9m114_stop_streaming(sensor);
> +
> +	pm_runtime_disable(&client->dev);
> +	if (!pm_runtime_status_suspended(&client->dev))
> +		mt9m114_power_off(sensor);
> +	pm_runtime_set_suspended(&client->dev);
> +}
> +
>  static const struct of_device_id mt9m114_of_ids[] = {
>  	{ .compatible = "onnn,mt9m114" },
>  	{ /* sentinel */ },
> @@ -2667,6 +2760,7 @@ static struct i2c_driver mt9m114_driver = {
>  	},
>  	.probe		= mt9m114_probe,
>  	.remove		= mt9m114_remove,
> +	.shutdown	= mt9m114_shutdown,
>  };
>  
>  module_i2c_driver(mt9m114_driver);
> diff --git a/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c b/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c
> index 2a90f86e515f..87f8ddcd6651 100644
> --- a/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c
> +++ b/drivers/staging/media/atomisp/pci/atomisp_csi2_bridge.c
> @@ -547,6 +547,7 @@ int atomisp_csi2_bridge_parse_firmware(struct atomisp_device *isp)
>  
>  err_parse:
>  		fwnode_handle_put(ep);
> +		v4l2_async_nf_cleanup(&isp->notifier);
>  		return ret;
>  	}
>  
> diff --git a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
> index 900a67552d6a..32a1f85ab598 100644
> --- a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
> +++ b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
> @@ -805,6 +805,9 @@ static void atomisp_unregister_entities(struct atomisp_device *isp)
>  	unsigned int i;
>  	struct v4l2_subdev *sd, *next;
>  
> +	v4l2_async_nf_unregister(&isp->notifier);
> +	v4l2_async_nf_cleanup(&isp->notifier);
> +
>  	atomisp_subdev_unregister_entities(&isp->asd);
>  	for (i = 0; i < ATOMISP_CAMERA_NR_PORTS; i++)
>  		atomisp_mipi_csi2_unregister_entities(&isp->csi2_port[i]);

-- 
Regards,

Laurent Pinchart