MBP 13 2020 won't recognize USB devices from TB dock after sleeping and connecting to the dock. After unplugging the dock MBP crashes and does SMC reset

Commenting in the hopes of gaining some traction. Still an issue under 10.15.7, apple thunderbolt display to TB3 adapter, as well as TB display connected to a Belkin TB2 dock. Constant crashes, USB not working (thought it was TBD USB hub at first).

This is a completely unacceptable solution, and has made my already bitter purchase of a 2020 MBA that can cook eggs on the processor that much more aggravating. This whole machine has been a complete disaster, was delivered with a blown left speaker (crackled, right out of the box). Everybody can gripe about the decline of apple, yadda yadda. I'll consider this a bad apple. But as a collector with over 50+ macs, I have to say, this has probably been the worst hardware + software package I've ever purchased from them...2020 MBA i5 16gb ram. Was so excited to finally replace my 2013 i7 MBA, a true champ.

Apple...get your stuff together, patch this already. You relegate us to a single port - USB C. You market it as the do-all port. Make it do.

P.S. - Healthcare industry worker, lost valuable data in a draft document due to this crash. My work computer is now unreliable to use as a workstation.

Device: MBP 13" 2020 i7

Catalina 10.15.7 (19H2)

Display: Apple recommended LG Ultrafine 5k with integrated dock

I have the same issue as the OP, and it is ongoing since I got my MBP2020 end of May.

Disconnecting the display usually works, using the MBP unconnected (except for power) afterwards as well, but when reconnecting the next day to the display I almost every time get a kernel panic, later "explained" by "Intel CrashLog recorded due to unexpected reset".

Or I have to manually restart to make USB (external Apple keyboard and Apple Touchpad) work again.

Or I get a total lockup where the external display shows nothing but what I now call the Psychedelic Beach Ball Of Death because it's the normal BBOD but spinning like crazy and colored in the orange/magenta range only. In this case, only forced shutdown (holding down touchID button > 10sec) helps.

The LG Ultrafine 5k is as close as it is possible to get to an "Apple" TB3 dock - they said they "worked with LG" back in 2016 to make this the best display for the then new TB3 MBPs.

It is definitely an Apple issue. And while it got really reproducible with the new MBP2020, the TB3/USB stack in macOS was unstable since the MBP2016, also in the MBP2018 and now in the MBP2020 to various degrees.

It looks to me as if Apple is just dukt taping this and that over time, shifting problem zones a bit, causing some uses cases to get working while ruining others, but apparently is not really able to find and fix the underlying problem at the root :-(

benjamin.lauret wrote:

Can you share the official answer from Apple.

I would love to, but I was told on the phone, and they declined to notify me in writing. I guess they don't want a paper trail, or evidence of how appalling they treat their customers. I have no issues with the support staff, who were professional and courteous, and could only deliver the message from the engineers, that shutting down the computer before unplugging a device is how you're supposed to unplug a TB3 device on a Mac.

I understand why nobody at Apple would want to put that in writing. Maybe someone want to explain that particular "engineer" that the 90s are over.

I'm allowing myself to make fun of the word engineer as I am one, working in the computing world :)

This is riduculous, I tested Big Sur Beta 11 and I saw some issues, but I'm not sure they are the same though.

Well, that´s indeed strange. In my Setup (same as above, except I´m running OS 10.15.7 Catalina and TS3+) the crashing also occurs in case the Computer goes to Stby while connected to the dock.

Scenario: leave connected to dock, go to lunch. Return and pick up Macbook (went to Stby meanwhile) for a Zoom meeting or so in another room. Finish, let go to Stby (lid closed) and go back to desk. Connect. Alas: Crash!

I tried with a whole lot of different samples (various Thunderbolt Cinema Displays, various Thunderbolt Cables, even got another brand new Macbook Pro 13" (4 Thunderbolts). Same thing all over.

Even in 10.15.7. Catalina. Even when not "Hot Disconnecting".

To all folks at Apple: This is a Macbook! Not a 97 Windows Computer that crashes 2 out of three when undocking!

Never believed engineers would fall to such lame excuse (I am one myself, working a few years as a Sw Architect ...)

That is an absolutely horrific response. I’m glad to hear Big Sur seemingly fixes this. But anything short of an admission that this is an open bug without a solution is a slap in the face to the pro consumers who are spending their time helping to fix this. Not to mention a slap in the face as general customers. By the way, I’ve seen multiple people state that this is a MacBook Pro issue and that this may be a small drop in the bucket relative to the user base, etc. It appears that this is across all 2020 macs. My MacBook Air has this problem. iMacs are just less likely to be hot swapping.

I think I’m going to have to put in a call to Apple support. This, on top of the dire thermal constraints of my laptop, are really making me want to return this thing. I will happily buy an Apple Silicon machine.

beezur wrote:

I will happily buy an Apple Silicon machine.

This is certainly not a good method how to say Apple you are not happy with their current support...

It's crazy how majority of Apple customers think - Apple sells stuff for premium prices and can't provide elementary support. They laugh and say thunderbolt is not intended to be hotplug and that we are using it wrong and Apple customers still go and buy another product. This is crazy. No wonder PC users call us sheeps.

The truth is that I have a 2010 iMac which has now had upgraded SSD, WiFi/bt, processor, ram, even graphics card. My laptop before this 2020 MBA was a 2013 MBA. I don’t unnecessarily give Apple my money. But I did think this was a good long term solution. It is not. I do need another long term solution, so if Apple Silicon is it, then I will gladly trade.

This is interesting news to me - I figured it only happened with my Apple Thunderbolt Cinema Display. But it seems like it´s connected to connecting any external display.

Which is a bummer for me: I can´t reboot my Laptop every time before I connect it to an external display - I use it frequently (several times a day) for giving presentations. And all the meeting rooms now use USB-C docks to connect to the display.

I have a clue to an interesting "fix" (but it´s not yet thoroughly investigated or confirmed):

My MacBook Pro 2020 has 4 Thunderbolt Interfaces. It seems (from looking at the System Report List) that each pair of these is connected to an individual Hardware Driver ("Thunderbolt 1" and "Thunderbolt 2"). Hot connect/disconnect seems to make these somehow "stuck", specifically in case the MBP went to Stby for more than 5 Minutes (Tea Break) during disconnect.

I simply tried to reconnect using the "other pair" of Thunderbolt/USB-C connectors on my MBP: disconnect from right side plug, go to Stby, get a cup of tea, re-connect to a plug on the left side. And: no crash. All fine.

I tried a couple times. And I had no time to investigate further or try more often. But no crash using this method:

Re-connect on the opposite side of your Macbook you were connected to previously.

Weird, eh?

My suspicion: someone forgot to implement an Interface to a reset function that may be invoked in the Thunderbolt controllers. However, such a function seems to be executed in case a connector is connected for the 1st time. This function seems to run on both HW controllers at the same time. Even if triggered by the "other" plug or HW. So, the function is there - just the interface to actually call it from the OS is missing.

Too complicated? never mind. Apple will know what I´m writing about ...

I guess you are spot on with this ;-)

Because just yesterday, I had the case when the machine did not crash on re-connect, but "only" all USB devices connected via the USB hub in the LG Ultrafine 5k were dead. So for a change, I plugged my USB hub from the display's USB port directly to one of the free TB3 ports on the other side of my MBP. It instantly connected all USB devices.

So obviously the messup caused by display disconnect seems local to the right or left TB3 controller, and the "other side" remains operational. I suspect however that simply changing sides does not work multiple times (and @logicito seems to confirm that).

I fully agree with you that this must be a incomplete cleanup on disconnect problem in the macOS USB/TB3 stack. Something in the controller or in the driver responsible for it gets stuck when the display is disconnected. Apparently, this can have different possible consequences - immediate crash, crash when re-connecting display, USB dead in reconnected display.

In my experience there's no clear pattern what happens when, so I guess it's just something with uninitialized memory, so while the cause is always the disconnect, the exact consequences are random. Sometimes it even works as it should (maybe 1 out of 10 disconnects)

I just updated to Big Sur Beta 10 today in hopes of resolving this and it *seems* to be working so far. Haven't seen the same kernel panic since, and I've un-docked and re-docked 3-4 times now.

Hardware:

2020 MBP13

Using CalDigit TS3 Dock

Same here. MBP 13 2020 and Elgato Thunderbolt 3 Pro dock. Super frustrating.

I have joined Big Sur beta to see if that might be a better experience, nope.

I get regular crashes as described here, as well as sound devices disappearing and monitors going to sleep randomly.

I have a new 2020 MacBook Air running macOS 10.15.7 and I get this error too after I shutdown. I have an Anker USB C Hub PowerExpand Direct 7-in-2 docking station https://www.amazon.com/gp/product/B07YZ48HCT/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1 with a 26" Dell monitor connected via HDMI. Almost ever time I shutdown the MacBook Air reboots with the below error. I send it to Apple every time. It is quite irritating.

panic(cpu 0 caller 0xffffff7f9c333b66): "[IGPU] sendHostToGucMessage: Firmware communication error: no action response!\n"@icl/sched3/IGGuC.cpp:3626

Same problem here with my MBP13 2020, caldigit dock, crash a lot, no connexion with my Thunderbolt Display. I need to restart to have to have the my second Display. When its waking up, the screen sometimes flash and I need to restart too. And when I unplug and close my Mac it restarts with the "Intel CrashLog recorded due to unexpected reset" error