| # Slow down autosuspend for hubs under dwc2 host port |
| # |
| # Autosuspend on dwc2's "host" port is pretty broken. When we see a "remote |
| # wakeup" we have to fully reset the port. |
| # |
| # If we disable autosuspend then the main downside is that security keys will |
| # take up more power. That's not so good for laptops. ...so we don't do it. |
| # We don't actually allow autosuspend for too many devices anyway. |
| # |
| # One type of thing that _does_ get autosuspend turned on is USB hubs. That |
| # means if you plug in an empty USB hub you'll see the "remote wakeup" when |
| # you plug the first device in. Though a bit gross, this isn't a huge deal. |
| # After all you're just re-enumerating an empty hub. |
| # |
| # ...but... |
| # |
| # It turns out that for at least one hub I looked at (an Amazon Basics one) |
| # the device goes back and autosuspends again quickly after we reset it. |
| # Thus we get into a loop that looks like this: |
| # |
| # 1. Plug in empty hub. |
| # 2. Empty hub autosuspends. |
| # 3. Plug in new device. |
| # 4. Hub does a remote wakeup to us because there's a device. |
| # 5. We wee the remote wakeup and reset (looks like plug / unplug of the hub). |
| # 6. Enumerate the hub. |
| # 7. Before we can enumerate the device in the hub, hub autosuspends. |
| # 8. Hub realizes that there's a device and does a remote wakeup. |
| # 9. Goto step #5 |
| # |
| # We can _sometimes_ get out of the loop if we win the race and enumerate the |
| # device before the hub suspends. |
| # |
| # Let's make the race a little more likely to be won by giving ourselves |
| # 1 second before we autosuspend things that originally were going to |
| # autosuspend after 0 seconds. |
| |
| ACTION=="add|change", KERNELS=="ff540000.usb", ATTR{product}!="DWC OTG Controller", ATTR{bDeviceClass}=="09", ATTR{power/autosuspend_delay_ms}=="0", ATTR{power/autosuspend_delay_ms}="1000" |
