(7.5) Intel I915 Dual monitors

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jagauthier
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Joined: 2020/09/30 19:43:23

(7.5) Intel I915 Dual monitors

Post by jagauthier » 2020/09/30 19:51:49

Greetings,

I realize 7.5 is fairly old, but at the present it's a requirement. I have a Dell Precision 55xx, with an Intel i915 in it. There's an HDMI cable available for external monitor access.

Unfortunately, only the laptop display is seen. I've goofed around with it for a little while, but I've been unable to figure out how to get the second monitor working.

I'd definitely appreciate some tips. What I have tried is looking at the output of xrandr, which is minimal.

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Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
   1920x1080     77.00* 
Thanks for the pointers.

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TrevorH
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Re: (7.5) Intel I915 Dual monitors

Post by TrevorH » 2020/09/30 20:25:03

Sorry but only the current version of CentOS gets any support. That's currently 7.8 and since RHEL 7.9 was released upstream earlier this week, soon it will be 7.9. And when talking about new hardware support, that gets added at point release time and thus anything that isn't supported in 7.5 will not ever be supported until you update to a more recent point release.

And all that doesn't even cover how dangerous it is to run a version of CentOS that is 2.5 years out of date. According to te RHEL errata page, there have been 31 security advisories that are marked as "Critical" since April 2018 when 7.5 came out. There have been nearly 300 in that same time period that are merely "Important". Your systems are vulnerable to all of those.

If you have a requirement to stay on a particular point release then you need to be looking at purchasing RHEL and their EUS subscription (an additional cost item) that does precisely that - it lets you stay on a single point release and still receive security updates.
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jagauthier
Posts: 2
Joined: 2020/09/30 19:43:23

Re: (7.5) Intel I915 Dual monitors

Post by jagauthier » 2020/10/01 11:54:08

Thanks. I realize it's old. There are reasons I have to stay on that version. Security isn't a concern. It's an air gapped network, it cannot, will not, and will never have access to another network, let alone the internet.

bonedome
Posts: 173
Joined: 2017/04/22 08:11:04

Re: (7.5) Intel I915 Dual monitors

Post by bonedome » 2020/10/01 17:26:15

Hello
to activate hdmi I use this command

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xrandr --output HDMI-1 --auto --set audio on
and to switch off laptop screen

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xrandr --output HDMI-1 --auto --set audio on --output LVDS-1 --off
To find the correct names for your monitors use

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xrandr -q
Alternatively you can use the gui version lxrandr, you'll have to build it from source http://www.linuxfromscratch.org/blfs/vi ... randr.html or rebuild a fedora 30 srpm (same version), it has practically no dependecies so is easy to build yourself.

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