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Francis Greaves

2016-Feb-22 16:18 UTC

[CentOS-virt] Garbled screen after RAM Scrub on boot

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 
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Scot P. Floess

2016-Feb-22 17:02 UTC

head link

[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

Francis Greaves

2016-Feb-22 17:51 UTC

head link

[CentOS-virt] Garbled screen after RAM Scrub on boot

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 at nc.rr.com> 
To: "Francis Greaves" <francis at choughs.net> 
Cc: "centos-virt" <centos-virt at 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 
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George Dunlap

2016-Feb-23 09:31 UTC

head link

[CentOS-virt] Garbled screen after RAM Scrub on boot

On Mon, Feb 22, 2016 at 4:18 PM, Francis Greaves <francis at choughs.net>
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?
Francis,

Thanks for reporting this.  I'd suggest re-posting your question on
xen-users -- there are a lot more eyeballs watching that list than
this one, and it's easier to "escalate" the issue to the
development
list from there.

My first instinct is wondering whether grub setting the graphics mode
is part of the problem.  Have you tried having grub just take the bios
text mode that was given it, rather than changing it?

(Obviously ideally Xen would work whatever the graphics mode is, but
most developers are accessing test boxes over serial in a colo, so
it's not the kind of thing they're prone to notice.)

 -George

Francis Greaves

2016-Feb-23 13:40 UTC

head link

[CentOS-virt] Garbled screen after RAM Scrub on boot

Dear George, 
Thanks for the input and ideas. 
Unfortunately bootscrub=false dos not work, not does setting nothing for vga,
still get the 'Little white squares'!
I am asking the xen-users as you suggest 
Regards, Francis 


From: "George Dunlap" <dunlapg at umich.edu> 
To: "Francis Greaves" <francis at choughs.net>,
"centos-virt" <centos-virt at centos.org>
Sent: Tuesday, 23 February, 2016 09:31:40 
Subject: Re: [CentOS-virt] Garbled screen after RAM Scrub on boot 

On Mon, Feb 22, 2016 at 4:18 PM, Francis Greaves <francis at choughs.net>
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? 
Francis, 

Thanks for reporting this. I'd suggest re-posting your question on 
xen-users -- there are a lot more eyeballs watching that list than 
this one, and it's easier to "escalate" the issue to the
development
list from there. 

My first instinct is wondering whether grub setting the graphics mode 
is part of the problem. Have you tried having grub just take the bios 
text mode that was given it, rather than changing it? 

(Obviously ideally Xen would work whatever the graphics mode is, but 
most developers are accessing test boxes over serial in a colo, so 
it's not the kind of thing they're prone to notice.) 

-George 
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