Date:   Fri, 17 Dec 2021 16:19:20 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Mathias Nyman <mathias.nyman@linux.intel.com>,
        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: <YbyqeE39vqE9pEDD@kroah.com>
References: <YajkzwmWQua3Kh6A@hirez.programming.kicks-ass.net>
 <105f35d2-3c53-b550-bfb4-aa340d31128e@linux.intel.com>
 <88f466ff-a065-1e9a-4226-0abe2e71b686@linux.intel.com>
 <972a0e28-ad63-9766-88da-02743f80181b@intel.com>
 <Yao35lElOkwtBYEb@kroah.com>
 <c2b5c9bb-1b75-bf56-3754-b5b18812d65e@linux.intel.com>
 <YbyWuxoBSicFBGuv@hirez.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <YbyWuxoBSicFBGuv@hirez.programming.kicks-ass.net>
Precedence: bulk

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.
> 
> > Seems to hang when read_poll_timeout_atomic() calls ktime_* functions.
> > Maybe  it's too early for ktime.
> 
> It certainly is, using ktime for delay loops sounds daft to me anyhow.

It was a "find a pattern and replace it with a function call" type of
cleanup series.  It's obviously wrong, I will go revert it now.

thanks,

greg k-h