WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] VGA extended text modes

To: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] VGA extended text modes
From: Gerd Knorr <kraxel@xxxxxxxxxxx>
Date: 28 Feb 2005 18:25:46 +0100
Cc: "Jared Rhine" <jared@xxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxxxx>, <ian.pratt@xxxxxxxxxxxx>
Delivery-date: Mon, 28 Feb 2005 17:32:13 +0000
Envelope-to: xen+James.Bulpin@xxxxxxxxxxxx
In-reply-to: <A95E2296287EAD4EB592B5DEEFCE0E9D1E32BF@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
Organization: SUSE Labs, Berlin
References: <A95E2296287EAD4EB592B5DEEFCE0E9D1E32BF@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
User-agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3
"Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx> writes:

> However, how does dom0 set the extended text mode? I presume it doesn't
> use a BIOS call.

Linux uses vesa bios calls in the 16bit startup code, at least for the
stuff settable via vga="...".  Mode info is passed to 32bit code in
struct screen_info (see Documentation/i386/zero-page.txt).  Thats why
the vga argument needs special treatment by the boot loaders, they
can't just pass it on on the kernel command line like most other args.
They have to set a byte in the kernel's boot sector for that.  See
also "man rdev".  That is really old stuff from the days you have
booted your new linux kernel using "cat zImage > /dev/fd0 && reboot".

For just more text lines you can simply load a smaller font than the
default one somewhere in the dom0 boot scripts to have the same
effect.  That doesn't work for 132col txt modes or graphic modes (=>
vesafb) though.

  Gerd

-- 
#define printk(args...) fprintf(stderr, ## args)


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel

<Prev in Thread] Current Thread [Next in Thread>