Cameras (IPU3): dw9719 VCM driver no longer binds on 6.19+ kernels — kills all cameras (missing i2c ID table) #2225

Environment

• Device: Surface Pro 5 (Surface_Pro_1796), i5-7300U
• Kernel: 6.19.8-surface-3 (from pkg.surfacelinux.com) — regression confirmed vs 6.14, whose dw9719 module still binds
• Distro: Linux Mint 22.3 (Ubuntu 24.04 base)
• Userspace: libcamera 0.3.0 with IPU3 pipeline (source build)

Summary

On 6.19-based surface kernels, all IPU3 cameras disappear (cam -l lists
nothing) because the dw9719 focus-motor (VCM) driver no longer binds to the
VCM i2c client that ipu-bridge instantiates. The sensor's swnode references
the VCM via lens-focus, so the cio2 async notifier never completes: no
sensor→CSI-2 media links are created, no sensor subdev nodes appear, and
libcamera registers zero cameras — including the front camera, which has no
VCM of its own.

Root cause

ipu_bridge_instantiate_vcm() creates the VCM i2c client with plain board-info
type "dw9719" (modalias i2c:dw9719). The current drivers/media/i2c/dw9719.c
only carries an OF match table (dongwoon,dw9719 etc.) and has no
i2c_device_id table, so i2c core matching never succeeds:

$ cat /sys/bus/i2c/devices/i2c-INT347A:00-VCM/modalias
i2c:dw9719

$ modinfo dw9719 | grep '^alias'
alias:          of:N*T*Cdongwoon,dw9800k...   (of: aliases only, no i2c: alias)

$ ls -l /sys/bus/i2c/devices/i2c-INT347A:00-VCM/driver
ls: cannot access ...: No such file or directory     <- never binds

Media graph state while broken (note sensors with 0 links):

- entity 39: ov8865 3-0010 (1 pad, 0 link, 0 routes)
- entity 43: ov5693 2-0036 (1 pad, 0 link, 0 routes)
$ cam -l
Available cameras:        <- empty

For comparison, the 6.14 (Ubuntu generic) dw9719 module still has the
i2c:dw9719 alias, and binding works there.

Fix (verified on the affected device)

Restoring the ID table makes the driver bind immediately; the notifier then
completes, links appear, and both cameras register and stream (verified with
libcamera + Cheese/Zoom via v4l2loopback):

static const struct i2c_device_id dw9719_id_table[] = {
	{ "dw9718s", DW9718S },
	{ "dw9719", DW9719 },
	{ "dw9761", DW9761 },
	{ "dw9800k", DW9800K },
	{ }
};
MODULE_DEVICE_TABLE(i2c, dw9719_id_table);

static struct i2c_driver dw9719_i2c_driver = {
	...
	.id_table = dw9719_id_table,
};

(dw9719_probe() already uses i2c_get_match_data(), so the id-table
driver_data slots in cleanly.)

Impact / affected devices

Any IPU3 device whose SSDB declares a dw9719-family VCM — at minimum the
Surface Pro 5/6 rear camera (ov8865 + dw9719). Devices with other VCM types
listed in ipu_vcm_types[] may be affected by the same OF-only pattern if
their drivers lost i2c ID tables too.

Ask

1. Could linux-surface carry this (tiny) patch in its kernel builds until it
   lands upstream?
2. Happy to send the patch to linux-media upstream if that helps — guidance
   welcome.

Workaround for users (until patched kernels ship)

A DKMS module that rebuilds the patched driver per-kernel works well; a
write-up with scripts is here: [DISCUSSION POST]