linux-kernel - Re: [PATCH] x86/efi: Add EFI framebuffer earlyprintk support

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Message-ID: <20131014075726.GB20435@gmail.com>
Date:	Mon, 14 Oct 2013 09:57:26 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Matt Fleming <matt@...sole-pimps.org>, linux-efi@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Matt Fleming <matt.fleming@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Jones <pjones@...hat.com>
Subject: Re: [PATCH] x86/efi: Add EFI framebuffer earlyprintk support


* H. Peter Anvin <hpa@...or.com> wrote:

> On 10/12/2013 10:49 AM, Ingo Molnar wrote:
> > 
> >>>> +static void early_efi_write_char(void *dst, char c, int h)
> >>>> +{
> >>>> +	const u8 *src;
> >>>> +	u32 fgcolor = 0xaaaaaa;
> >>>
> >>> That's RGB grey, right? Why not 0xffffff for a very visible white?
> >>  
> >> The VGA earlyprintk code uses the equivalent grey, AFAIK, which is why I 
> >> picked this value.
> > 
> > The VGA code should be changed to white too I suspect ;-)
> > 
> 
> For compatibility with the classical text console we use light grey as 
> the default color and a double-stroked font (which was necessary on the 
> CGA display since it didn't have enough bandwidth to handle 
> single-stroked fonts well).  The problem with changing that to white is 
> that you end up with a mismatch between the earlyprintk console and the 
> "real" console, *or* we change the behavior of everyone's consoles...

Btw., I have no problem at all with making the early console look separate 
and making it clear when we switch to the 'real' console.

earlyprintk is a debug method, and more information can only be good. 

Thanks,

	Ingo
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