Hot to boot CentOS 7 in text console mode 80x25 ?

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AlainTH
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Hot to boot CentOS 7 in text console mode 80x25 ?

Post by AlainTH » 2014/09/12 11:41:21

Hello folks,

I've tried just about anything I could find to no avail. I have CentOS 7 booting inside an ESXi VM in text console mode, and it insists in going to 160x48 characters mode which I don't want.
No combination of kernel command line option like "nomodeset", "vga=785", "video=640x400" etc. seems to do anything, CentOS 7 stubbornly insists in switching to this 160x48 mode at some point during boot from the good old 80x25 mode inherited from Grub.
I'm sure I must be missing something obvious, but I'm really out of options here and starting to really hate this new version 7 (just as if getting rid of good old startup shell scripts weren't enough for an old timer like me...)
There's an article entitled "How to set the VGA console text resolution to 80x25 in RHEL 6 and RHEL 7" in Red Hat's knowledge base. That sounds really promising but unfortunately it seems to be behind their paywall :(

Would anyone kindly help? thanks in advance.

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AlainTH
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Location: France

Re: Hot to boot CentOS 7 in text console mode 80x25 ?

Post by AlainTH » 2014/09/12 13:20:34

Sorry if I'm kind of replying to myself here.
Actually the title of this topic should really specify "CentOS 7 as an ESX guest" because it does seem to matter.
I'm not sure whether a general solution can be given to my question, but in my particular case things revolve around the vmwgfx kernel module.
I assume there must be some way to pass a forced video mode setting to this module, but I haven't found it. However, adding "vmwgfx.enable_fbdev=0" to the kernel command line (in /etc/default/grub then rebuild Grub configuration) did the trick for me, my CentOS 7 VM now boots all the way in good old-fashioned 80x25 text mode.
Note: VMware Tools are not loaded yet. This module obviously comes with the vanilla kernel.

berndbausch
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Me too (Re: Hot to boot CentOS 7 in text console mode 80x25

Post by berndbausch » 2014/11/14 11:37:48

Actually the title of this topic should really specify "CentOS 7 as an ESX guest" because it does seem to matter.


Well, in my case I am running Centos 7 in a KVM virtual machine (hosted, luckily, on Centos 6.5), and the problem is exactly the same.

UPDATE: I found the answer a few minutes later. See next post.
Last edited by berndbausch on 2014/11/14 11:47:46, edited 1 time in total.

berndbausch
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Re: Hot to boot CentOS 7 in text console mode 80x25 ?

Post by berndbausch » 2014/11/14 11:46:07

Kernel parameter video=640x480 did the trick for me. The output of some initialization messages is garbled, but it was so before, and was unreadable anyway. I guess experimenting with other resolutions and other fonts might get rid of that problem.

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