Re: kernel boot fail with efi earlyprintk (bisected)

[Dave Young <dyoung@redhat.com>]

On 08/21/14 at 09:52pm, Matt Fleming wrote:
> On Tue, 19 Aug, at 04:16:58PM, Dave Young wrote:
> > Hi,
> > 
> > 3.16 kernel boot fail with earlyprintk=efi on my laptop.
> > It keeps scrolling at the bottom line of screen.
> > 
> > Bisected, the first bad commit is below:
> > commit 86dfc6f339886559d80ee0d4bd20fe5ee90450f0
> > Author: Lv Zheng <lv.zheng@intel.com>
> > Date:   Fri Apr 4 12:38:57 2014 +0800
> > 
> >     ACPICA: Tables: Fix table checksums verification before installation.
> > 
> > 
> > I did some debugging by enabling both serial and efi earlyprintk, below is
> > some debug dmesg, seems early_ioremap fails in scroll up function due to
> > no free slot, but I'm still not sure if the debug info is right or not.
> 
> Thanks Dave, your callstack seems to make sense.
> 
> Can you also enable early_ioremap_debug so that we can figure out where
> all the FIXMAP slots are going?

With early_ioremap_debug enabled, there will be a lot of "dropped printk", so
I can not get any useful information.

Will try to do more debug.

Thanks
Dave