Date:   Fri, 14 Jan 2022 09:47:42 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mathias Nyman <mathias.nyman@linux.intel.com>
Cc:     Greg KH <gregkh@linuxfoundation.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Lu Baolu <baolu.lu@linux.intel.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        Chunfeng Yun <chunfeng.yun@mediatek.com>
Subject: Re: earlyprintk=xdbc seems broken
Message-ID: <YeE4rtq6t73OxOi+@hirez.programming.kicks-ass.net>
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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.