Good Day,

I have a problem with dual monitors on a HP desktop running Linux Mint 18.

When both monitors are attached, they show the LM logo and then go into standby mode after cold booting. Nothing can awaken them. The computer will not respond to any keystrokes or mouse movement. I have to turn off the power to shutdown the computer.

Each monitor works individually on either VGA or DVI-D cable. The posts that I have read about similar problems seem to be about video card driver conflicts. I am using the stock video/graphics connection attached to the mother board. Any suggestions or solutions?

Thanks

The driver must support dual displays. Also, you can't use 2 different gpus at once, unless the mobo is designed for that. I don't know if the 2 ports are using different gpus. On systems designed for dual display, generally the 2 ports are of the same type. On many systems with VGA and DVI, you simply can't use them both at once.

1 members found this post helpful.

So what you are saying is I have to bite the bullet and buy a pci card with either two vga ports or two dvi-d ports to support dual monitors?

flackbait, it could be a good idea to open up the machine and have a look at where the ports go. are they both connected more-or-less directly to the mobo, or is 1 (or even both) of them connected to a PCI plugin card?

are both ports identical or is one vga and one dvi, or something else?

edit:
output of
might be helpful.

I would need to know what motherboard/graphics chip set you have, how the BIOS sees the monitors (can you get into the BIOS with both monitors connected?) and what DPMS settings you have on each monitor. Also do you have input auto-select turned on on both monitors?

Also why do you have to turn off the power to the PC to awaken the monitors? Can you not power cycle them alone? And if you can what happens?

Can you connect to the machine over a network connection (SSH, Telnet, VPN, etc)? Is there any disk activity once the monitors go dark?

To give you some back ground I use two monitors connected the builtin graphics on an Gigbyte motherboard, one via HDMI and the other via VGA. The motherboard will not support both DVI and HDMI in use at the same time!
My main machine has two Nvidia cards in it, using the Nvidia driver. Over that I run X with FVWM on top and get one desktop spanning four monitors seamlessly. Each monitor is connected via HDMI, two monitors to each card. I can not use the more common desktops as they will not support multiple graphics cards (or rather the libraries/toolkits they are build on will not do it). Both Gnome3 and KDE5 use one card or the other, but not both at the same time. I used to be able to run KDE4 with my set-up but when they upgraded (and moved to QT5) everything broke, and they have still not fixed it. Same goes from Gnome, 2 worked but 3 does not. Neither KDE4 or Gnome2 are being updated so now I gave gone back to FVWM which just works, and I have managed to write stuff that makes it work much like KDE, but with better multi-head support.

Thanks for responding

I found the specs for my HP pavillion p7-1234 on the official HP website. The specs say that the dvi and vga can be used at the same time. The VGA and DVI ports are hardwired to the MB. Is there some switch that has to be thrown to get Mint to handle both? This machine came loaded with Windows 7 and was forced at gun point to upgrade to windows 10. I got tired of all the Microsoft B.S and went to Linux Mint one year ago. MY wife got a taste of dual monitors on a Windows computer at work and wants it on our home computer.

here is the results from the command line.


flackbait@flackbait-p7-1234 ~ $ lspci -k | grep -iEA5 'vga|3d|display'
00:01.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] BeaverCreek [Radeon HD 6530D]
Subsystem: Hewlett-Packard Company BeaverCreek [Radeon HD 6530D]
Kernel driver in use: radeon
Kernel modules: radeon
00:02.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Family 12h Processor Root Port
DeviceName: Onboard IGD
flackbait@flackbait-p7-1234 ~ $

I let the terminals auto select. The computer is unresponsive after the terminals go on standby. I have tired repeated cold boots and the results are the same. Two monitors in standby. I have to disconnect the cable to one of the monitors and cold boot to get things working. No network. This computer is a standalone. NO cards in PCI slots.

I can't get to LM with dual monitors connected. It doesn't get there. I don't get a home screen. Black screen and unresponsive

It would seem that you are not alone in having this problem, this link is one of many that reports something very similar.
The reason I have included it is that is has a solution that might work for you:

https://ubuntuforums.org/showthread.php?t=2210877

But you say you get the LM logo before they go black, so something must be working.

Do you have any means of configuring the monitors when you have the GUI running on just one screen?

Also can you switch to the command line (ctrl+alt+f1) and login there?

If you can at least login on the command line, it will prove it is just a configuration problem.

That has not been my experience. As a matter of fact, I have not run into ANY systems that have both a VGA and DVI connector (a very common combination) where you couldn't have two monitors working simultaneously. I've used probably a dozen systems like this and never had one of those fail to support dual monitors. Caveat: These are older systems, where "on-board graphics" means "implemented on the motherboard". Newer systems have on-board graphics that are supported by the CPU.

Now, I DO have a current system that I just built where the motherboard has THREE connectors - an HDMI, a DVI and a DisplayPort connector. And only two of those work simultaneously by default. However, if you install the ASUS motherboard drivers that come on a CD included with the MoBo, then all three ports work simultaneously. This is in Windows of course, since those driver CD's are typically useless in Linux. However, ASUS may have equivalent drivers for Linux available - I just didn't look for them. (This most recent built that I did HAD to be Windows, for very specific software application reasons.)

On your computer, assuming it's a newer model, the "on board graphics" are probably supported by the CPU, not solely by the MoBo as in years past. So the CPU *and* the MoBo must *both* support dual monitors. Since you bought this pre-built from HP, they certainly should have verified this in their design. I looked at their website for your model and clear as day, it says "DVI and VGA ports (Use of both the VGA and DVI ports at the same time is supported)". But realize, that may be for Windows, and only if appropriate motherboard drivers are installed. Remember the days way back when, when we had modems (telephone modems, not cable modems!) There was a period where Linux users had to be careful in their modem choices, because there were these beasts often called "WinModems" that would only work with Windows, using special drivers. Linux users were out of luck with these beasts, and they had to be avoided. There is a possibility that we are entered a similar era where we have "WinGraphics". I don't know that for sure, but I'm starting to suspect it.

Per HP's website, your MoBo setup is composed of the following:

Manufacturer: Pegatron
Model: AAHD2-HY (Holly)
Chipset: AMD Hudson-D2 FCH
CPU: AMD A6 3650

I would call HP tech support (hope you get a smart one!) and describe your problem. Obviously mentioning Linux for sure. You could also try calling Pegatron, but chances are that is some generic MoBo manufacturer in a third world country where they don't even have phones, let alone speak English. Do some very specific Google searching to see if you can turn up info on Linux with this specific motherboard, chipset, and CPU related to graphics and drivers.

I will give HP a call in the AM. I will also try the solution suggested by Radeon. The worst that can happen is that I have to buy a pci video board that is linux friendly for a seven year old machine.

my first thought after looking at the lspci output was that maybe the machine supports dual monitors, but not the radeon driver.
i would boot with one monitor, try to find a solution for that (i guess installing the proprietary driver could be one), then hope it works again with both.

So, you do not a hardware problem, as LinuxMint produces a logo...

then moves into a mode or modes that the displays do not support and kills keyboard input.

Have you tried preventing Xorg from starting? Hit the e key as soon as the Grub menu paints, and append '3 splash=0 plymouth.enable=0' to the kernel command line before proceeding. Do you subsequently see boot messages on either or both displays, and then get a login prompt on either or both displays?