[RFC PATCH] USB: core: emit a device-level modalias

[Giuseppe Piscitelli <ooonea@gmail.com>]

USB device drivers can load from interface modaliases after a userspace
client has already configured the device. Loading apple-mfi-fastcharge
then reprobes the generic binding and interrupts usbmuxd transfers.

Emit a modalias on the device event, with unknown interface fields left
as wildcards. The existing udev module loader can load matching modules
before consumers receive the processed device event. Keep interface
modaliases and the driver teardown paths unchanged.

Signed-off-by: Giuseppe Piscitelli <ooonea@gmail.com>
Assisted-by: OpenAI Codex
---
Tested on x86_64 with Linux 7.2.9 and an iPhone (05ac:12a8). With no
Apple module preload, the first insertion after boot loads the module,
keeps configuration 4 and works with iLoader without restarting usbmuxd.
The current usb_uevent function also passes 18 source-extracted cases.

 drivers/usb/core/driver.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 3c3bbaf89..29d1acba9 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -954,6 +954,17 @@ static int usb_uevent(const struct device *dev, struct kobj_uevent_env *env)
 			   usb_dev->descriptor.bDeviceProtocol))
 		return -ENOMEM;
 
+	if (is_usb_device(dev) &&
+	    add_uevent_var(env,
+			   "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic*isc*ip*in*",
+			   le16_to_cpu(usb_dev->descriptor.idVendor),
+			   le16_to_cpu(usb_dev->descriptor.idProduct),
+			   le16_to_cpu(usb_dev->descriptor.bcdDevice),
+			   usb_dev->descriptor.bDeviceClass,
+			   usb_dev->descriptor.bDeviceSubClass,
+			   usb_dev->descriptor.bDeviceProtocol))
+		return -ENOMEM;
+
 	return 0;
 }
 

base-commit: 42bcac323cc3b16566fed8c5b250318ad02a0de0