I get the same effect of screen blank on memory scrub.

Just as a test try turning off the memory scrub in the xen boot options.

I wonder if xen overwrites the video-ram memory as its cleaning up.

On 02/22/2016 01:06 PM, Scot P. Floess wrote:
Francis,

I just rebooted my Precision 470 and watched...nothing :(

I see the boot menu, and then everything goes blank - as in just a blinking cursor until I get the login prompt.

No idea what it's doing - but I don't even see the scrubbing free memory output...

On Mon, 22 Feb 2016, Francis Greaves wrote:

Yes I usually work headless, but I have been setting it up from new, so need to see what is going on.
Regards
Francis


_________________________________________________________________________________________________________________________________________________________
From: "Scot P. Floess" <sfloess@nc.rr.com>
To: "Francis Greaves" <francis@choughs.net>
Cc: "centos-virt" <centos-virt@centos.org>
Sent: Monday, 22 February, 2016 17:02:12
Subject: Re: [CentOS-virt] Garbled screen after RAM Scrub on boot

When I was running Fedora 23 and using Xen (as the host OS), I saw
something similar on my Dell Precision 470.  I don't recall seeing it now
with CentOS 7, but I tend to boot that machine headless more than not...

On Mon, 22 Feb 2016, Francis Greaves wrote:

> Dear All
> I am using Centos 7 with Xen 4.6 on a Dell Poweredge T430
> When the machine boots, after the 'Scrubbing Free RAM' message, I get a screen filled with little white squares until the login prompt, so I cannot see
> what is happening as the machine boots. Also there is nothing on the screen when I reboot.
>
> My /etc/default/grub is
>
> GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
> GRUB_DEFAULT=saved
> GRUB_DISABLE_SUBMENU=true
> GRUB_CMDLINE_LINUX="crashkernel=auto rhgb intremap=no_x2apic_optout"
> GRUB_CMDLINE_XEN_DEFAULT="dom0_mem=13312M,max:14336M dom0_max_vcpus=6 dom0_vcpus_pin"
> GRUB_GFXMODE=1024x768
> GRUB_GFXPAYLOAD_LINUX=keep
> GRUB_CMDLINE_LINUX_XEN_REPLACE_DEFAULT="console=hvc0 earlyprintk=xen nomodeset"
>
> I have tried setting (for a 1024x768 resolution) vga=792 in the GRUB_CMDLINE_LINUX and commenting out GRUB_GFXMODE and GRUB_GFXPAYLOAD_LINUX, but this
> makes no difference
>
> What am I doing wrong?
>
> Regards
> Francis
>
>

Scot P. Floess             RHCT  (Certificate Number 605010084735240)
Chief Architect FlossWare  http://sourceforge.net/projects/flossware
                            http://flossware.sourceforge.net
                            https://github.com/organizations/FlossWare



Scot P. Floess             RHCT  (Certificate Number 605010084735240)
Chief Architect FlossWare  http://sourceforge.net/projects/flossware
                           http://flossware.sourceforge.net
                           https://github.com/organizations/FlossWare


_______________________________________________
CentOS-virt mailing list
CentOS-virt@centos.org
https://lists.centos.org/mailman/listinfo/centos-virt


-- 
Alvin Starr                   ||   voice: (905)513-7688
Netvel Inc.                   ||   Cell:  (416)806-0133
alvin@netvel.net              ||