Re: earlyprintk=xdbc seems broken

From: Peter Zijlstra
Date: Fri Jan 14 2022 - 03:48:02 EST


On Tue, Dec 21, 2021 at 10:40:50AM +0100, Peter Zijlstra wrote:
> On Fri, Dec 17, 2021 at 02:55:07PM +0100, Peter Zijlstra wrote:
> > On Fri, Dec 17, 2021 at 01:01:43PM +0200, Mathias Nyman wrote:
> > > I can reproduce this.
> > > Looks like problems started when driver converted to readl_poll_timeout_atomic() in:
> > >
> > > 796eed4b2342 usb: early: convert to readl_poll_timeout_atomic()
> >
> > I can confirm, reverting that solves the boot hang, things aren't quite
> > working for me though.
>
> I've been poking at this a little, find debug patch and full dmesg
> below. The TL;DR version of the dmesg seems to be:
>
> [ 4.984148] xhci_dbc:xdbc_start: waiting for connection timed out
> [ 4.984149] xhci_dbc:early_xdbc_setup_hardware: failed to setup the connection to host
>
> Initially I thought this was due to delay not being set up properly, but
> I 'fixed' that, and I've ran out of ideas. I really don't know anything
> about USB :/

Any thoughts on this? I'd really like to be able to use this machine but
can't due to lack of console.