TWO full-HD displays on a Windows 10 Guest?

Discussions about using Windows guests in VirtualBox.
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Fred Mau
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TWO full-HD displays on a Windows 10 Guest?

Post by Fred Mau »

Host system is Oracle Linux 8 running on a HP Z240 Workstation which is driving (3) HP 24" monitors at "Full HD" (1920 x 1080) resolution via the 3 onboard displayport connections. GPU is "Intel HD Graphics 530" which I've assigned 512MB ram in the bios. All the monitors display just fine on the host at full HD.

I want to use (2) of those displays at Full HD resolution in a Windows 10 (Enterprise LTSC, build1809) guest. I've got monitor count set to (2) and VRAM set to 256 MB which is supposedly as high as I can go, though Windows 10 reports it as 384 MB.

PROBLEM IS, In windows I can set display #1 to 1920x1080 just fine... but I don't have an option for going above 1400 x 1050. I don't *think* I'm running out of VRAM; even if I drop display #1 down to 1024x768, I STILL can't go above 1400 x 1050 for display #2. It's as if maybe the VboxSVGA driver has that as a hard limit for display #2? Or is there an ini file somewhere that can be modified?

I seem to recall that in older versions of windows, you could go in to video properties and uncheck a box called "show only supported resolutions" or something like that, but I don't see any equivalent in Windows 10.
scottgus1
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Re: TWO full-HD displays on a Windows 10 Guest?

Post by scottgus1 »

Start the VM from full power off, not save-state. Try to set the screen sizes as best you can, then shut down the VM from within the VM OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Please right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.
Fred Mau
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Re: TWO full-HD displays on a Windows 10 Guest?

Post by Fred Mau »

It is attached

What I meant to say in my original post is that I can get the FIRST display in the W10 guest to go to 1920 x 1080, but that the SECOND display won't go above 1400 x 1050.
Attachments
VM_W10C_WCCES-2021-07-01-12-43-05.zip
(35.55 KiB) Downloaded 12 times
scottgus1
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Re: TWO full-HD displays on a Windows 10 Guest?

Post by scottgus1 »

Everything looks well-built in the VM, and I see the two screens taking 1920x1080 and 1400 x 1050. I don't see why the VM shouldn't be able to go higher in the second screen.

Could be the VM is out of video RAM to run 2 1920x1080's with 3D acceleration enabled.

Try reducing the 1920x1080 screen to a smaller value, see if the 1400x1050 screen can then go bigger. If it can, then maybe it's just too much for 256MB to run.
Fred Mau
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Re: TWO full-HD displays on a Windows 10 Guest?

Post by Fred Mau »

I've tried reducing screen #1 to 1024 x 768, didn't help. I've even tried rebooting the VM after reducing the resolution on screen #1 but it doesn't 'stay' at 1024 x 768, as soon as it boots up it goes to 1920 x 1080. Turning 3D acceleration on or off doesn't seem to matter either way.

I've noticed something odd: It's not just 1920 x 1080 I can't do on screen #2; I don't have an option for ANY 16:9 resolution on screen #2, not even a small one like 1366×768
scottgus1
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Re: TWO full-HD displays on a Windows 10 Guest?

Post by scottgus1 »

Fred Mau wrote:I don't have an option for ANY 16:9 resolution
We had a topic pn this recently. Apparently the "monitor" Virtualbox presents to the VM is a 4:3 monitor. A few of us tried many things, but could not get 16:9 screen sizes in the VM OS unless the VM window was set to the size by going full-screen on a 16:9 host monitor or using vboxmanage conmmands or the View menu. I don't have the link, though.
Fred Mau wrote:even if I drop display #1 down to 1024x768, I STILL can't go above 1400 x 1050 for display #2.
Sorry, just noticed you'd posted this in the first post.

If you go to the VM window's View menu, then 'Virtual Screen2', does the VM respond to the 16:9 choices there? There is a 1920x1080 option.

Also, what happens when you put the VM into Full-Screen mode?
mpack
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Re: TWO full-HD displays on a Windows 10 Guest?

Post by mpack »

Fred Mau wrote:I've tried reducing screen #1 to 1024 x 768, didn't help
Do not mix aspect ratios on one monitor! - that never happens in the physical world, so it's a complete tossup what any OS will do with that. 1024x768 has a 4x3 aspect ratio, on a monitor you said previously was widescreen.

Windows in particular will very helpfully disable display size options that don't match the aspect ratio of your monitor. To convince windows otherwise you need to carefully drag the window borders until you achieve the perfect aspect ratio (yes, avoid fullscreen for now). Then shut down the VM. Then start it again. Now Windows should notice that you have a widescreen monitor. If you are careful thereafter not to mix aspect ratios per monitor then Windows should not get confused.

Also, in the VirtualBox manager preferences, try setting File|Preferences|Display Max Guest Screen Size to None.
Fred Mau
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Re: TWO full-HD displays on a Windows 10 Guest?

Post by Fred Mau »

scottgus1 wrote:
Fred Mau wrote:I don't have an option for ANY 16:9 resolution
We had a topic pn this recently. Apparently the "monitor" Virtualbox presents to the VM is a 4:3 monitor. A few of us tried many things, but could not get 16:9 screen sizes in the VM OS unless the VM window was set to the size by going full-screen on a 16:9 host monitor or using vboxmanage conmmands or the View menu. I don't have the link, though.
Fred Mau wrote:even if I drop display #1 down to 1024x768, I STILL can't go above 1400 x 1050 for display #2.
Sorry, just noticed you'd posted this in the first post.

If you go to the VM window's View menu, then 'Virtual Screen2', does the VM respond to the 16:9 choices there? There is a 1920x1080 option.

Also, what happens when you put the VM into Full-Screen mode?
Well, this is interesting. I was going to post about how i'd tried all that and I still couldn't get beyond 1400 x 1050 on screen #2. Then I got handed another project that took a week or so, just got back on this today.

So I was going to boot up the VM and post o picture of what I was seeing and the settings and .... whaddya know.... It suddenly started working. And I made absolutely no changes between when it didn't work and now, except that over the past week or so both the Windows 10 Guest VM and the Oracle Linux 8 Host machine have been rebooted several times.

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