usbmux breaks Touch Bar, ALS, and camera on MacBookPro's

[roadrunner2]

When running on a MacBookPro, commits ec5ff91 and 8a69f1a cause usbmux to misconfigure (configuration 0 is not a valid config) the iBridge device (T1 chip), breaking Touch Bar, light sensor, and camera functionality. The problem was originally reported at roadrunner2/macbook12-spi-driver#42.

I don't really understand the usbmux in any detail, so not sure how to fix this exactly, but it seems like you need to distinguish between internal USB devices and external ones plugged into the system, and avoid touching the internal ones.

[mexmer]

usbmuxd is not supposed to be run on OSX, it has own mux server

[nikias]

@mexmer I think he is running it on Linux on the MacBook Pro.

[mexmer]

oh i see.

now question is, how to limit usbmux only to ios devices, without need to explicitly list them.
i mean, you can put up list of vid&pid that it should react to ... but that is not exactly best approach.
same if you do blacklist (eg. list of devices it should not react to), either whitelist or blacklist will need to be updated with every new hardware release.

[nikias]

@mexmer I am working on it with @rickmark.

[nikias]

On Linux, configuration 0 basically means the device is "unconfigured". Not sure why this breaks though; the kernel driver should know about this. Anyway, I think maybe the 8600 device might just need a different rule. Can you guys tell me what the "normal" config of the T2 is? Does it work after modifying the udev rule to set it to 1 on the 8600 (T2)? Try this patch:

diff --git a/udev/39-usbmuxd.rules.in b/udev/39-usbmuxd.rules.in
index ab20517..7f9bf10 100644
--- a/udev/39-usbmuxd.rules.in
+++ b/udev/39-usbmuxd.rules.in
@@ -4,7 +4,8 @@
 SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*|5ac/8600/*", TAG+="systemd"

 # Initialize iOS devices into "deactivated" USB configuration state and activate usbmuxd
-SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*|5ac/8600/*", ACTION=="add", ENV{USBMUX_SUPPORTED}="1", ATTR{bConfigurationValue}="0", OWNER="usbmux", @udev_activation_rule@
+SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*", ACTION=="add", ENV{USBMUX_SUPPORTED}="1", ATTR{bConfigurationValue}="0", OWNER="usbmux", @udev_activation_rule@
+SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/8600/*", ACTION=="add", ENV{USBMUX_SUPPORTED}="1", ATTR{bConfigurationValue}="1", OWNER="usbmux", @udev_activation_rule@

 # Make sure properties don't get lost when bind action is called
 SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*|5ac/8600/*", ACTION=="bind", ENV{USBMUX_SUPPORTED}="1", OWNER="usbmux", @udev_activation_rule@

/cc @davidjo

Don't forget to rebuild and reinstall so the udev rule gets updated.

[davidjo]

For quick fix just copy the 39-udevadm.rules file from Ubuntu 20.04 (which is missing all |5ac/8600 additions) and touchbar is restored.

[nikias]

@davidjo @roadrunner2 did you ever test my patch? I am wondering if this would just resolve the issue...

[davidjo]

I just tried this - but get a syslog error
systemd-udevd[353]: /usr/lib/udev/rules.d/39-usbmuxd.rules:7 Invalid key/value pair, ignoring.
systemd-udevd[353]: /usr/lib/udev/rules.d/39-usbmuxd.rules:8 Invalid key/value pair, ignoring.

lines 7 8 are the green lines in your patch

of course the message doesnt say which key is the problem

(so touchbar works because udev doesnt understand the file so ignores it)

[night199uk]

On Linux, configuration 0 basically means the device is "unconfigured". Not sure why this breaks though; the kernel driver should know about this. Anyway, I think maybe the 8600 device might just need a different rule. Can you guys tell me what the "normal" config of the T2 is? Does it work after modifying the udev rule to set it to 1 on the 8600 (T2)? Try this patch:

diff --git a/udev/39-usbmuxd.rules.in b/udev/39-usbmuxd.rules.in
index ab20517..7f9bf10 100644
--- a/udev/39-usbmuxd.rules.in
+++ b/udev/39-usbmuxd.rules.in
@@ -4,7 +4,8 @@
 SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*|5ac/8600/*", TAG+="systemd"

 # Initialize iOS devices into "deactivated" USB configuration state and activate usbmuxd
-SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*|5ac/8600/*", ACTION=="add", ENV{USBMUX_SUPPORTED}="1", ATTR{bConfigurationValue}="0", OWNER="usbmux", @udev_activation_rule@
+SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*", ACTION=="add", ENV{USBMUX_SUPPORTED}="1", ATTR{bConfigurationValue}="0", OWNER="usbmux", @udev_activation_rule@
+SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/8600/*", ACTION=="add", ENV{USBMUX_SUPPORTED}="1", ATTR{bConfigurationValue}="1", OWNER="usbmux", @udev_activation_rule@

 # Make sure properties don't get lost when bind action is called
 SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{PRODUCT}=="5ac/12[9a][0-9a-f]/*|5ac/190[1-4]/*|5ac/8600/*", ACTION=="bind", ENV{USBMUX_SUPPORTED}="1", OWNER="usbmux", @udev_activation_rule@

/cc @davidjo

Don't forget to rebuild and reinstall so the udev rule gets updated.

This patch actually seems to work great. I see it's been a while since this bug was updated. Any chance this patch could get integrated, as with Touch Bar support now in the mainline kernels this would fix the OOTB Touch Bar experience on most T1/T2 Macs.

[davidjo]

could you post the actual 39-usbmuxd.rules here - hadnt realized this is a pre-cursor file which is filled in and setting up the makefile seems complicated as it just replaces the udev_activation_rule parameter with other parameters which is not clear where they are defined.
(This explains my symbol issues).