Enabling framebuffer on a CentOS 7?

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TrevorH
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Re: Enabling framebuffer on a CentOS 7?

Post by TrevorH » 2017/09/21 14:28:48

Yes, that's a linode kernel not ours. Ask them how to run the CentOS kernel or how to enable it on theirs.
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ylluminate
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Re: Enabling framebuffer on a CentOS 7?

Post by ylluminate » 2017/09/21 14:39:28

Are you seeing the precise module to ask for for KVM-QEMU video virtualization at this point? The article to which I linked is a bit dated and what I'm seeing otherwise seems to be for Windows guests on Linux (Virtio discussions). I'm hunting for guest CentOS 7 chatter in terms of video modules, but it seems that no one really cares about video performance / virtualization (not that I care about performance, but just want to get the framebuffer functioning of course).

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Re: Enabling framebuffer on a CentOS 7?

Post by TrevorH » 2017/09/21 14:51:51

No idea which of the 66 lines from my grep turn on the specific thing you're looking for. My first step would be to see if you can switch to the distro kernel as a) that probably has the right options turned on out of the box and b) I bet it gets updated for security vulnerabilities a lot more often than the linode version.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
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ylluminate
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Re: Enabling framebuffer on a CentOS 7?

Post by ylluminate » 2017/09/21 14:54:06

That might not be a bad idea. I hate to lose any optimizations that they might have in place for performance purposes - if there are any.

Looks like CentOS 7 is running Linux 3.10 currently while Linode's is up to 4.9. Any idea of what I could be losing on the outside by shifting over? I suspect that going with the distro kernel is the most sane route at this point, especially to at least get to where the framebuffer is working and see what is actually missing.

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Re: Enabling framebuffer on a CentOS 7?

Post by TrevorH » 2017/09/21 15:04:59

Given that Redhat backport many many changes from the mainline kernel to their 3.10 one, probably not much. Last time I looked at the rpm changelog (rpm -q --changelog kernel-3.10.0-693.2.2el7) it had around 60,000 lines of changes made to it since the initial release of RHEL 7.0.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
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ylluminate
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Re: Enabling framebuffer on a CentOS 7?

Post by ylluminate » 2017/09/21 15:49:39

Yeah, good call. I'll run with the distro instead. It's easy enough to flip to it, but I would like to know what I'm missing. I'll try to work with their support to get to the bottom of whether or not I'll have any adverse ramifications for the changeover.

So after the switchover, good news is that `/dev/fb0` is already available. Bad news is that TeamViewer still gripes about it:

Code: Select all

$teamviewer setup

The framebuffer console seems to be unavailable or has the wrong format. Please make sure that /dev/fb0 is accessible and it is configured to 32-bit depth.
Must be something still off or perhaps it is simply some kind of a "wrong format" issue...

ylluminate
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Re: Enabling framebuffer on a CentOS 7?

Post by ylluminate » 2017/09/22 15:01:49

I also tried a suggestion as noted here wherein I added the following to `/etc/default/grub`:

Code: Select all

GRUB_GFXMODE=1024x768x32
GRUB_GFXPAYLOAD_LINUX=keep
I then executed:

Code: Select all

sudo grub2-mkconfig -o /boot/grub2/grub.cfg
Unfortunately it appears that whatever is required as far as the framebuffer goes and what TeamViewer needs is still not being met as I'm still meeting with the same failure.

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Re: Enabling framebuffer on a CentOS 7?

Post by TrevorH » 2017/09/22 15:07:04

Are you sure your user has access to the FB device?

Code: Select all

crw-rw----. 1 root video 29, 0 Sep  9 00:31 /dev/fb0
So it has to be a member of group video or root here.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

ylluminate
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Re: Enabling framebuffer on a CentOS 7?

Post by ylluminate » 2017/09/22 18:19:36

Yes:

Code: Select all

crw-rw----. 1 root video 29, 0 Sep 22 14:47 /dev/fb0

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Re: Enabling framebuffer on a CentOS 7?

Post by TrevorH » 2017/09/22 21:30:23

And your user? Is it part of the video group?
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

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