Xen devel - May 2008 - xen "vga=" console mode set in ubuntu /boot/grub/menu.lst is ignored

On Tue, May 20, 2008 at 6:55 AM, Keir Fraser <keir.fraser@eu.citrix.com>
wrote:
	> Hey, I''m not on xen-users. Please post a new thread on xen-devel
with a
	> clear explanation of the problem for those who haven''t seen the
xen-users
	> context.

ok.  $$$ sez i get barked at for cross-posting ;-)

> On 5/17/08, snowcrash+xen@gmail.com <schneecrash+xen@gmail.com>
wrote:
>>
>> i''ve nominal ubuntu 804 installed as a xen 320 Dom0,
>>
>>        Linux server 2.6.24-16-xen #1 SMP Thu Apr 10 14:35:03 UTC 2008
>> x86_64 GNU/Linux
>>
>> i''m trying to setup the console video mode that xen uses, but
am
>> failing to do so.
>>
>> presuming,
>>
>>        # VESA video modes (VGA codes):
>>                640x480 800x600 1024x768 1280x1024 1600x1200 Ask user at
>> boot.
>>        8 bits  vga=769 vga=771 vga=773  vga=775   vga=796   vga=ask
>>        16 bits vga=785 vga=788 vga=791  vga=794   vga=798   vga=ask
>>        32 bits vga=786 vga=789 vga=792  vga=795   vga=799   vga=ask
>>
>> which seems to be backed up by,
>>
>>
>> http://slackware.osuosl.org/slackware-3.3/docs/linux-2.0.30/svga.txt
>>
>> i edit "/boot/grub/menu.lst" to
>>
>>        ### BEGIN AUTOMAGIC KERNELS LIST
>>        ...
>>        # xenhopt=dom0_mem=512M noirqdebug vga=775
>>        # xenkopt=max_loop=64 console=tty0 console=ttyS0,115200n8
>>        ...
>>
>> then, a subsequent
>>
>>        update-grub
>>
>> re-generates "/boot/grub/menu.lst" to contain,
>>
>>        title       Xen 3.2 / Ubuntu 8.04, kernel 2.6.24-16-xen
>>        root        (hd0,0)
>>        kernel      /xen-3.2.gz dom0_mem=512M noirqdebug vga=775
>>        module      /vmlinuz-2.6.24-16-xen ro
>> root=/dev/mapper/VG_Dom0-LV_ROOT max_loop=64 console=tty0
>> console=ttyS0,115200n8
>>        module      /initrd.img-2.6.24-16-xen
>>
>> on reboot,  @console Xen begins to dsiplay its output, but stops at
>>
>>        press <RETURN> to see video modes
>>        <SPACE> to continue, or wait 30 sec
>>
>> here i can select any of the offered video modes, and boot continues
>> in the selected video mode.
>>
>> or, i can wait 30 sec, and vid mode defaults to 80x25 text, and boot
>> continues.
>>
>> i just can''t get the mode to ''stick'' to what
i set in menu.lst.
>>
>> any ideas? something wrong/additional needed in config?

On Mon, May 19, 2008 at 7:06 PM, Ray Barnes <tical.net@gmail.com>
wrote:
> I tried playing with these under a late RC of Xen 3.2.0, i.e. setting my
> terminal to a static vga mode or a static number of lines (50, 60) and
found
> it to be horribly broken - this on an Asus DSBV-DX board with the XGI video
> chip.  Nothing seemed to work except a lines setting of 50 or 60
(can''t
> remember which) gave me 30 something lines of text; none of the VGA modes
> worked properly under the Xen kernel, yet no problem under the CentOS
> 5.1 supplied kernel.  FYI, the video modes referenced in the
kernel''s
> vga.txt document are _not_ supported on a 1 to 1 basis under Xen; look at
> the source code for supported modes.  If you can''t find them, try
reasking
> on xen-devel and I''m sure Kier can spout them off the top of his
head.  As
> far as I could tell at the time, he was the last committer to mess with
> screen modes.

On Tue, May 20, 2008 at 6:39 AM, snowcrash+xen@gmail.com
<schneecrash+xen@gmail.com> wrote:
> ray,
>
>> none of the VGA modes worked properly under the Xen kernel, yet no
problem
>> under the CentOS 5.1 supplied kernel.
>
> testing, i can also now reproduce the problem on an opensuse 11-beta3
install.
>
> but, as you''ve found, on a vanilla centos51 install, no issues (at
> least not with the VGA modes ...)
>
> so, looks like something in xen 32x''s changed ...
>
>> try reasking on xen-devel and I''m sure Kier can spout them off
the top of his
>> head.  As far as I could tell at the time, he was the last committer to
mess with
>> screen modes
>
> rather than move this thread, i''ll keep it here, and copy him.
>
> thanks for the heads-up!
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On 20/5/08 15:10, "snowcrash+xen@gmail.com"
<schneecrash+xen@gmail.com>
wrote:
> On Tue, May 20, 2008 at 6:55 AM, Keir Fraser
<keir.fraser@eu.citrix.com>
> wrote:
>> Hey, I''m not on xen-users. Please post a new thread on
xen-devel with a
>> clear explanation of the problem for those who haven''t seen
the xen-users
>> context.
> 
> ok.  $$$ sez i get barked at for cross-posting ;-)
This is an easy one. Xen''s vga= syntax is a bit different than
Linux''s. You
can actually specify a vga= option of the form gfx-WxHxD. For example for
16-bit 1024x768:
 vga=gfx-1024x768x16

 -- Keir



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keir,

On Tue, May 20, 2008 at 7:18 AM, Keir Fraser <keir.fraser@eu.citrix.com>
wrote:
> This is an easy one. Xen''s vga= syntax is a bit different than
Linux''s. You
> can actually specify a vga= option of the form gfx-WxHxD. For example for
> 16-bit 1024x768:
>  vga=gfx-1024x768x16
i apparently, then, have a gift for googling-without-finding; i had
not seen that syntax :-/

per suggestion, vga=gfx-1024x768x16 works great. thanks.

random attempt @ vga=gfx-1280x1024x24 does not, bringing up the
''select video mode'' again.

somewhere (looking some more ...) there''s a doc specifying the
xen-allowed video modes?  looking here @ src,

   http://lists.xensource.com/archives/html/xen-changelog/2007-06/msg00206.html

it''s not immediately obvious

thanks!

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On 20/5/08 15:36, "snowcrash+xen@gmail.com"
<schneecrash+xen@gmail.com>
wrote:
> i apparently, then, have a gift for googling-without-finding; i had
> not seen that syntax :-/
> 
> per suggestion, vga=gfx-1024x768x16 works great. thanks.
> 
> random attempt @ vga=gfx-1280x1024x24 does not, bringing up the
> ''select video mode'' again.
> 
> somewhere (looking some more ...) there''s a doc specifying the
> xen-allowed video modes?  looking here @ src,
> 
>    
>
http://lists.xensource.com/archives/html/xen-changelog/2007-06/msg00206.html
> 
> it''s not immediately obvious
We support pretty much any mode that a modern VGA BIOS will advertise. Often
the 24-bit formats are actually 32-bit. So you might find that
vga=gfx-1280x1024x32 will work.

You can see all available modes on a particular system by scrolling through
them when you specify vga=ask. You can then pick one and hardcode it in your
GRUB config.

 -- Keir



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