[libcamera-devel] [PATCH v3] libcamera: device_enumerator: ensure deviceNode is not empty

[Benjamin Bara]

From: Benjamin Bara <benjamin.bara at skidata.com>

When activating both ISP nodes on the i.MX8MP, but only connecting one
camera sensor, libcamera aborts because it couldn't find the chosen
entity's device node:

[37:54:40.779902250] [3631] DEBUG DeviceEnumerator device_enumerator.cpp:252 Added device /dev/media1: rkisp1
[37:54:40.780196750] [3631] DEBUG DeviceEnumerator device_enumerator_udev.cpp:322 All dependencies for media device /dev/media0 found
[37:54:40.780237875] [3631] DEBUG DeviceEnumerator device_enumerator.cpp:252 Added device /dev/media0: rkisp1
[37:54:40.780505125] [3631] DEBUG Camera camera_manager.cpp:152 Found registered pipeline handler 'PipelineHandlerRkISP1'
[37:54:40.780599875] [3631] DEBUG DeviceEnumerator device_enumerator.cpp:312 Successful match for media device "rkisp1"
[37:54:40.780731375] [3631] ERROR V4L2 v4l2_device.cpp:93 'rkisp1_isp': Failed to open V4L2 device '': No such file or directory

Fix this by skipping empty device nodes:

[37:49:05.172672000] [3603] DEBUG DeviceEnumerator device_enumerator_udev.cpp:322 All dependencies for media device /dev/media1 found
[37:49:05.172720625] [3603] DEBUG DeviceEnumerator device_enumerator.cpp:256 Added device /dev/media1: rkisp1
[37:49:05.172973875] [3603] DEBUG DeviceEnumerator device_enumerator_udev.cpp:322 All dependencies for media device /dev/media0 found
[37:49:05.173012125] [3603] DEBUG DeviceEnumerator device_enumerator.cpp:256 Added device /dev/media0: rkisp1
[37:49:05.173281625] [3603] DEBUG Camera camera_manager.cpp:152 Found registered pipeline handler 'PipelineHandlerRkISP1'
[37:49:05.173376875] [3603] DEBUG DeviceEnumerator device_enumerator.cpp:107 Skip rkisp1_isp: no device node
[37:49:05.173414375] [3603] DEBUG DeviceEnumerator device_enumerator.cpp:316 Successful match for media device "rkisp1"
[37:49:05.173671250] [3603] DEBUG V4L2 v4l2_videodevice.cpp:632 /dev/video1[15:cap]: Opened device platform:rkisp1: rkisp1: rkisp1_stats
[37:49:05.173775125] [3603] DEBUG V4L2 v4l2_videodevice.cpp:632 /dev/video2[16:out]: Opened device platform:rkisp1: rkisp1: rkisp1_params
[37:49:05.173880500] [3603] DEBUG V4L2 v4l2_videodevice.cpp:632 /dev/video0[18:cap]: Opened device platform:rkisp1: rkisp1: rkisp1

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Signed-off-by: Benjamin Bara <benjamin.bara at skidata.com>
---
Hi!

The dots look like this:

/dev/media0:
digraph board {
        rankdir=TB
        n00000001 [label="{{<port0> 0 | <port1> 1} | rkisp1_isp\n | {<port2> 2 | <port3> 3}}", shape=Mrecord, style=filled, fillcolor=green]
        n00000001:port2 -> n00000006:port0
        n00000001:port3 -> n0000000d [style=bold]
        n00000006 [label="{{<port0> 0} | rkisp1_resizer_mainpath\n | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
        n00000006:port1 -> n00000009 [style=bold]
        n00000009 [label="rkisp1_mainpath\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
        n0000000d [label="rkisp1_stats\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
        n00000011 [label="rkisp1_params\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
        n00000011 -> n00000001:port1 [style=bold]
        n0000001d [label="{{<port0> 0} | csis-32e40000.csi\n | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
        n0000001d:port1 -> n00000001:port0
}

/dev/media1:
digraph board {
        rankdir=TB
        n00000001 [label="{{<port0> 0 | <port1> 1} | rkisp1_isp\n/dev/v4l-subdev0 | {<port2> 2 | <port3> 3}}", shape=Mrecord, style=filled, fillcolor=green]
        n00000001:port2 -> n00000006:port0
        n00000001:port3 -> n0000000d [style=bold]
        n00000006 [label="{{<port0> 0} | rkisp1_resizer_mainpath\n/dev/v4l-subdev1 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
        n00000006:port1 -> n00000009 [style=bold]
        n00000009 [label="rkisp1_mainpath\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
        n0000000d [label="rkisp1_stats\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
        n00000011 [label="rkisp1_params\n/dev/video5", shape=box, style=filled, fillcolor=yellow]
        n00000011 -> n00000001:port1 [style=bold]
        n0000001d [label="{{<port0> 0} | csis-32e50000.csi\n/dev/v4l-subdev2 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
        n0000001d:port1 -> n00000001:port0
        n00000022 [label="{{} | imx327 8-001a\n/dev/v4l-subdev3 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
        n00000022:port0 -> n0000001d:port0
}
---
Changes in v3:
- adapt check (thx to Kieran)
- Link to v2: https://lists.libcamera.org/pipermail/libcamera-devel/2023-June/038182.html

Changes in v2:
- adapt commit message
- Link to v1: https://lists.libcamera.org/pipermail/libcamera-devel/2023-June/038181.html
---
 src/libcamera/device_enumerator.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/libcamera/device_enumerator.cpp b/src/libcamera/device_enumerator.cpp
index f2e055de..42b5ba6c 100644
--- a/src/libcamera/device_enumerator.cpp
+++ b/src/libcamera/device_enumerator.cpp
@@ -101,8 +101,14 @@ bool DeviceMatch::match(const MediaDevice *device) const
 
 		for (const MediaEntity *entity : device->entities()) {
 			if (name == entity->name()) {
-				found = true;
-				break;
+				if (!entity->deviceNode().empty()) {
+					found = true;
+					break;
+				} else {
+					LOG(DeviceEnumerator, Debug)
+						<< "Skip " << entity->name()
+						<< ": no device node";
+				}
 			}
 		}
 

---
base-commit: 0ee9339331c648232e87d2de2ccd5a92cc61cab2
change-id: 20230609-empty-devnode-36dd2647cde0

Best regards,
-- 
Benjamin Bara <benjamin.bara at skidata.com>