Peanut gallery comment: assuming this situation is relatively rare, would a notification with an action button to reconnect be a fine compromise?

The situation is less rare than one thinks. In LON for example the commuter
train can go into tunnels ~ every 5 min or so on certain routes.

I'm not sure that the notification solution is necessarily the correct thing to do. From the Chromebook's point of view, there is no difference between when a connection is dropped due to going out of range, due to losing service, due to the user explicitly pressing the "disconnect" button on the phone to disable the hotspot, or due to a period of inactivity by the user (recall that the hotspot is auto-disabled after 10 minutes without use).

For the first two cases, the proposed notification solution seems viable, but for the latter two cases, the notification could be seen as "spammy" since the user has indicated that the user no longer needs the connection for now.

Additionally, once the connection dies, there is no guarantee that the phone is in range anymore, so we may not even be able to attempt a new connection. Thus, showing a notification upon disconnection would also be the wrong thing here, since clicking "reconnect" would not be able to start a connection.

To your last point, Kyle, my suggestion was only to show the notification when we know the phone is in range and has data (not to show the notification at the point of disconnect).

Thanks for the clarification - that removes the risk of my final point in comment #3 (not being able to attempt a reconnection).

That being said, we still need to consider how we would determine whether the device lost connection "accidentally" (the tunnel situation) or "explicitly" (the disconnect button and inactivity situations) to decide whether we'd show a notification.

Sorry I may not be aware how instant tethering works, but isn't it the case that if connection drops because of tunnel, the link between the phone and laptop will stay as it is (just no Internet) whereas when user disconnects on the phone end, the link will break?

kirillov@: I was under the impression that the Wi-Fi hotspot on the phone gets shut down automatically when there is no mobile data connection on the phone, though I've never tested this myself since I don't really experience times where there is no service. Are you saying that the Tether connection is NOT disconnected when you go through the tunnel? If so, I may have misunderstood your original feedback. Can you please clarify? Thanks!

IIRC hotspot wont shut off if phone loses connection. I normally use it on my way to work and it survives tunnels just fine, although internet obviously doesn't work there.

Thanks for the information.

kirillov@: Can you clarify what is happening when you pass through tunnels? What exactly is disconnecting?

Nothing disconnects, laptop thinks it has connection, hotspot stays active, but websites are not loading.

I see - in that case, can you clarify what the issue you're facing is? Are you saying that after the phone regains connectivity, your Chromebook's tether connection still cannot access the Internet?

When I'm using personal hotspot, connection restores nicely

When I'm using Instant Tethering, connection doesn't restore.

I chatted with kirillov@ a bit off-thread to get some clarity on exactly what's happening.

Using manual Wi-Fi hotspot:
(1) Connect to Wi-Fi hotspot.
(2) Drive through tunnel; this causes the phone to lose mobile service.
(3) Wi-Fi connection stays constant (even though there is no Internet access).

Using Instant Tethering:
(1) Connect to a phone via Instant Tethering.
(2) Drive through tunnel; this causes the phone to lose mobile service.
(3) This causes the Instant Tethering connection to disconnect.

The bug, then, is that Tether networks become disconnected when the phone loses service, but this does not happen using a manual Wi-Fi hotspot.

kirillov@, please reproduce this issue, then file feedback using Alt+Shift+I. In your feedback text, please include "Forward this bug to khorimoto@" so that the issue can be routed to me. Thanks!

Hey folks - I am on this, but didn't have a chance to repro that just yet.

Tried to repro today but after 5 minutes of waiting mobile phone didn't appear in the list of networks. I'm assuming it is a KI and not filing a feedback for this one.

kirillov@: There are several known Bluetooth bugs which, when they occur, prevent your Chromebook from exchanging message with your phone. When these occur, they result in symptoms like what you are seeing. Intel (Bluetooth chip manufacturer) is working on fixes for these bugs, and we hope to have the fixes in place soon.

Until then, when you see these errors, please turn your machine off and then back on again; this should reset the Bluetooth controller and get things working again. Let us know if you can reproduce this error again once you do that - thanks!

Updated: today I was in a situation when issue should've been repro'd but
it didn't. I'll try again tomorrow.