Re: [PATCH] efi earlyprintk fix

From: Matt Fleming
Date: Wed Nov 06 2013 - 04:39:10 EST


On Wed, 06 Nov, at 05:23:35PM, Dave Young wrote:
> On 11/04/13 at 08:58pm, Dave Young wrote:
> > On 11/04/13 at 10:37am, Matt Fleming wrote:
> > > On Sun, 03 Nov, at 08:16:47PM, Dave Young wrote:
> > > >
> > > > there's below one line shift problem:
> > > >
> > > > ACPI=0xdabfe000 ACPI 2.0=0xdabfe014 SMBIOS=0xdaa9e000
> > > > [ 0.000000] efi:
> > > >
> > > > In fact check efi_y and the lfb_height should be compared at the begin of the
> > > > loop of early_efi_write
> > >
> > > Hmm... this is interesting. I can't produce this on any of my machines.
> > > Where did you see this? What hardware?
> >
> > It's my laptop Thinkpad T420, the screen scolls very fast, I use boot_delay=500
> > to verify it with my patch for moving boot_delay param an early param.
> >
> > Even without boot_delay, there's always a line at bottom with only the prefix:
> > "efi:"
>
> I will do further debug if I got time on this. It's really helpful for having efi
> earlyprintk, thanks for your excellent idea of printing to efi fb!

Thanks. I suspect the code in early_efi_setup() that sets up efi_y is
somehow wrong.

--
Matt Fleming, Intel Open Source Technology Center
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