Intel HD 4000 and three monitors

[chrisb]

I read here that "3 monitors are support by Ivybridge only if 2 of those are identical and running at the same resolution (such as DP+DP, HDMI+HDMI etc)." I also read at Phoronix that "This means that two of the three outputs need to have the same connection type and same timings. However, most people in a triple monitor environment will have at least two -- if not all three -- of the monitors be identical and configured the same, so this shouldn't be a terribly huge issue." I have also seen this graphic (which I think might have come from Intel originally) suggesting that only systems with dual DisplayPorts can use three monitors (which is also repeated in the Intel FAQ).

So my question is - has anybody actually got three identical monitors running off the integrated graphics with, say, HDMI+HDMI+DVI? I can't find any reports where someone says they did it and it worked. Are there any mITX motherboards which support this? Or have dual DisplayPort?

The only SFF system I could find that should work is the Dell 9010, which has dual DisplayPort and VGA (not ideal). I do have three identical monitors with DVI-D (same clock) so according to the freedesktop people it should work, I am just sceptical as I have not seen a single person who says "works for me".

[ChrisXY]

On my notebook the internal notebook monitor and two identical external monitors, one with DVI and one with HDMI running at the same time, works. That's all I have tested so far.

The point is that not only must the resolution be the same, also the refresh rates must match. If you use

xrandr --verbose

you can see the modes like this:

  1920x1080 (0x53)  148.5MHz +HSync +VSync *current +preferred
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock   67.5KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   60.0Hz

I'm not sure what exactly needs to match but it's at least that last number, 60.0Hz in my case.

Sometimes activating the two external monitors is a bit buggy such that one doesn't get correctly enabled the first time but generally it works.

[chrisb]

  1920x1080 (0x53)  148.5MHz +HSync +VSync *current +preferred
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock   67.5KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   60.0Hz

I'm not sure what exactly needs to match but it's at least that last number, 60.0Hz in my case.

As far as I know, it's the pixel clock that has to match - that would be 148.5MHz above.

[chrisb]

For anyone else interested in this topic, I found an old post here that reports 3 monitors working ok with a DisplayPort+HDMI+DVI setup.

[nadrimajstor]

I have some issues with triple monitor configuration on HD4000

I'm testing KINO-QM770-R10 motherboard

Display Interfaces

• DVI-I (VGA+DVI) integrated in the Intel® QM77 (up to 1920 x 1200 @60Hz)
• 18/24-bit dual-channel LVDS support (up to 1920 x 1200 @60Hz)
• Dual HDMI output supported (up to 1920 x 1200 @60H

I'm testing following configuration:

• LVDS disabled via jumpers
• 1650x1050 on VGA1
• 1920x1080 on DP2
• 1920x1080 on DP3

Kernel v3.5 hangs on boot if there is any monitor connected to DP2
With v3.9 I'm able to pass boot section, however issuing:

xrand --output VGA1 --auto --output DP2 --auto --output DP3 --auto

triggers the same continuous errors:

...
[drm:intel_dp_set_signal_levels], Using signal levels 00000000
[drm:intel_dp_set_signal_levels], Using signal levels 02000000
[drm:intel_dp_set_signal_levels], Using signal levels 04000000
...

Here is some details on this bug I filled on Ubuntu Launchpad

Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192
VGA1 connected 1024x768+0+0 (0x50) normal (normal left inverted right x axis y axis) 433mm x 271mm
	Identifier: 0x42
	Timestamp:  257387
	Subpixel:   unknown
	Gamma:      1.0:1.0:1.0
	Brightness: 1.0
	Clones:    
	CRTC:       0
	CRTCs:      0 1 2
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	EDID:
		00ffffffffffff004c2d7c023032454d
		051201030e2b1b782aee95a3544c9926
		0f5054bfef80b30081808140714f0101
		0101010101017c2e90a0601a1e403020
		3600b10f1100001a000000fd00384b1e
		510e000a202020202020000000fc0053
		796e634d61737465720a2020000000ff
		00483958513131313636300a2020008c
  1680x1050 (0x49)  119.0MHz +HSync -VSync +preferred
        h: width  1680 start 1728 end 1760 total 1840 skew    0 clock   64.7KHz
        v: height 1050 start 1053 end 1059 total 1080           clock   59.9Hz
  1280x1024 (0x4a)  135.0MHz +HSync +VSync
        h: width  1280 start 1296 end 1440 total 1688 skew    0 clock   80.0KHz
        v: height 1024 start 1025 end 1028 total 1066           clock   75.0Hz
  1280x1024 (0x4b)  108.0MHz +HSync +VSync
        h: width  1280 start 1328 end 1440 total 1688 skew    0 clock   64.0KHz
        v: height 1024 start 1025 end 1028 total 1066           clock   60.0Hz
  1280x960 (0x4c)  108.0MHz +HSync +VSync
        h: width  1280 start 1376 end 1488 total 1800 skew    0 clock   60.0KHz
        v: height  960 start  961 end  964 total 1000           clock   60.0Hz
  1152x864 (0x4d)  108.0MHz +HSync +VSync
        h: width  1152 start 1216 end 1344 total 1600 skew    0 clock   67.5KHz
        v: height  864 start  865 end  868 total  900           clock   75.0Hz
  1024x768 (0x4e)   78.8MHz +HSync +VSync
        h: width  1024 start 1040 end 1136 total 1312 skew    0 clock   60.1KHz
        v: height  768 start  769 end  772 total  800           clock   75.1Hz
  1024x768 (0x4f)   75.0MHz -HSync -VSync
        h: width  1024 start 1048 end 1184 total 1328 skew    0 clock   56.5KHz
        v: height  768 start  771 end  777 total  806           clock   70.1Hz
  1024x768 (0x50)   65.0MHz -HSync -VSync *current
        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock   48.4KHz
        v: height  768 start  771 end  777 total  806           clock   60.0Hz
  832x624 (0x51)   57.3MHz -HSync -VSync
        h: width   832 start  864 end  928 total 1152 skew    0 clock   49.7KHz
        v: height  624 start  625 end  628 total  667           clock   74.6Hz
  800x600 (0x52)   50.0MHz +HSync +VSync
        h: width   800 start  856 end  976 total 1040 skew    0 clock   48.1KHz
        v: height  600 start  637 end  643 total  666           clock   72.2Hz
  800x600 (0x53)   49.5MHz +HSync +VSync
        h: width   800 start  816 end  896 total 1056 skew    0 clock   46.9KHz
        v: height  600 start  601 end  604 total  625           clock   75.0Hz
  800x600 (0x54)   40.0MHz +HSync +VSync
        h: width   800 start  840 end  968 total 1056 skew    0 clock   37.9KHz
        v: height  600 start  601 end  605 total  628           clock   60.3Hz
  800x600 (0x55)   36.0MHz +HSync +VSync
        h: width   800 start  824 end  896 total 1024 skew    0 clock   35.2KHz
        v: height  600 start  601 end  603 total  625           clock   56.2Hz
  640x480 (0x56)   31.5MHz -HSync -VSync
        h: width   640 start  664 end  704 total  832 skew    0 clock   37.9KHz
        v: height  480 start  489 end  491 total  520           clock   72.8Hz
  640x480 (0x57)   31.5MHz -HSync -VSync
        h: width   640 start  656 end  720 total  840 skew    0 clock   37.5KHz
        v: height  480 start  481 end  484 total  500           clock   75.0Hz
  640x480 (0x58)   30.2MHz -HSync -VSync
        h: width   640 start  704 end  768 total  864 skew    0 clock   35.0KHz
        v: height  480 start  483 end  486 total  525           clock   66.7Hz
  640x480 (0x59)   25.2MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock   31.5KHz
        v: height  480 start  490 end  492 total  525           clock   60.0Hz
  720x400 (0x5a)   28.3MHz -HSync +VSync
        h: width   720 start  738 end  846 total  900 skew    0 clock   31.5KHz
        v: height  400 start  412 end  414 total  449           clock   70.1Hz
HDMI1 disconnected (normal left inverted right x axis y axis)
	Identifier: 0x43
	Timestamp:  257387
	Subpixel:   unknown
	Clones:    
	CRTCs:      0 1 2
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	Broadcast RGB:	Automatic
		supported: Automatic    Full         Limited 16:2
	audio:	auto
		supported: force-dvi    off          auto         on          
DP1 disconnected (normal left inverted right x axis y axis)
	Identifier: 0x44
	Timestamp:  257387
	Subpixel:   unknown
	Clones:    
	CRTCs:      0 1 2
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	Broadcast RGB:	Automatic
		supported: Automatic    Full         Limited 16:2
	audio:	auto
		supported: force-dvi    off          auto         on          
HDMI2 disconnected (normal left inverted right x axis y axis)
	Identifier: 0x45
	Timestamp:  257387
	Subpixel:   unknown
	Clones:    
	CRTCs:      0 1 2
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	Broadcast RGB:	Automatic
		supported: Automatic    Full         Limited 16:2
	audio:	auto
		supported: force-dvi    off          auto         on          
HDMI3 disconnected (normal left inverted right x axis y axis)
	Identifier: 0x46
	Timestamp:  257387
	Subpixel:   unknown
	Clones:    
	CRTCs:      0 1 2
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	Broadcast RGB:	Automatic
		supported: Automatic    Full         Limited 16:2
	audio:	auto
		supported: force-dvi    off          auto         on          
DP2 connected 1024x768+0+0 (0x50) normal (normal left inverted right x axis y axis) 640mm x 360mm
	Identifier: 0x47
	Timestamp:  257387
	Subpixel:   unknown
	Gamma:      1.0:1.0:1.0
	Brightness: 1.0
	Clones:    
	CRTC:       1
	CRTCs:      0 1 2
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	EDID:
		00ffffffffffff00410c000001010101
		07160103804024780af9aba2554a9a25
		0f474a21080081800101010101010101
		010101010101023a801871382d40582c
		450080682100001e1b2150a051001e30
		48883500806821000018000000fc0050
		48494c495053204654560a20000000fd
		00384c1e5311000a20202020202001ca
		020326714e9f10202122140513041102
		15060126090703150750830100006703
		0c002000b82d023a80d072382d40102c
		458080682100001e011d803e73382d40
		7e2c458080682100001e011d80d0721c
		1620102c258080682100009e011d00bc
		52d01e20b828554080682100001e0000
		0000000000000000000000000000001c
	Broadcast RGB:	Automatic
		supported: Automatic    Full         Limited 16:2
	audio:	auto
		supported: force-dvi    off          auto         on          
  1920x1080 (0x5b)  148.5MHz +HSync +VSync +preferred
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock   67.5KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   60.0Hz
  1920x1080 (0x5c)  148.5MHz +HSync +VSync
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock   56.2KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   50.0Hz
  1920x1080i (0x5d)   74.2MHz +HSync +VSync Interlace
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock   33.8KHz
        v: height 1080 start 1084 end 1094 total 1125           clock   30.0Hz
  1920x1080i (0x5e)   74.2MHz +HSync +VSync Interlace
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock   28.1KHz
        v: height 1080 start 1084 end 1094 total 1125           clock   25.0Hz
  1920x1080 (0x5f)   74.2MHz +HSync +VSync
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock   33.8KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   30.0Hz
  1920x1080 (0x60)   74.2MHz +HSync +VSync
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock   28.1KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   25.0Hz
  1920x1080 (0x61)   74.2MHz +HSync +VSync
        h: width  1920 start 2558 end 2602 total 2750 skew    0 clock   27.0KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   24.0Hz
  1280x1024 (0x4b)  108.0MHz +HSync +VSync
        h: width  1280 start 1328 end 1440 total 1688 skew    0 clock   64.0KHz
        v: height 1024 start 1025 end 1028 total 1066           clock   60.0Hz
  1360x768 (0x62)   84.8MHz -HSync -VSync
        h: width  1360 start 1432 end 1568 total 1776 skew    0 clock   47.7KHz
        v: height  768 start  771 end  776 total  798           clock   59.8Hz
  1280x720 (0x63)   74.2MHz +HSync +VSync
        h: width  1280 start 1390 end 1430 total 1650 skew    0 clock   45.0KHz
        v: height  720 start  725 end  730 total  750           clock   60.0Hz
  1280x720 (0x64)   74.2MHz +HSync +VSync
        h: width  1280 start 1720 end 1760 total 1980 skew    0 clock   37.5KHz
        v: height  720 start  725 end  730 total  750           clock   50.0Hz
  1024x768 (0x50)   65.0MHz -HSync -VSync *current
        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock   48.4KHz
        v: height  768 start  771 end  777 total  806           clock   60.0Hz
  800x600 (0x54)   40.0MHz +HSync +VSync
        h: width   800 start  840 end  968 total 1056 skew    0 clock   37.9KHz
        v: height  600 start  601 end  605 total  628           clock   60.3Hz
  720x576 (0x65)   27.0MHz -HSync -VSync
        h: width   720 start  732 end  796 total  864 skew    0 clock   31.2KHz
        v: height  576 start  581 end  586 total  625           clock   50.0Hz
  720x480 (0x66)   27.0MHz -HSync -VSync
        h: width   720 start  736 end  798 total  858 skew    0 clock   31.5KHz
        v: height  480 start  489 end  495 total  525           clock   59.9Hz
  640x480 (0x59)   25.2MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock   31.5KHz
        v: height  480 start  490 end  492 total  525           clock   60.0Hz
  640x480 (0x67)   25.2MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock   31.5KHz
        v: height  480 start  490 end  492 total  525           clock   59.9Hz
DP3 connected 1024x768+0+0 (0x50) normal (normal left inverted right x axis y axis) 510mm x 290mm
	Identifier: 0x48
	Timestamp:  257387
	Subpixel:   unknown
	Gamma:      1.0:1.0:1.0
	Brightness: 1.0
	Clones:    
	CRTC:       2
	CRTCs:      0 1 2
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
	EDID:
		00ffffffffffff001e6d2f57182e0200
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	Broadcast RGB:	Automatic
		supported: Automatic    Full         Limited 16:2
	audio:	auto
		supported: force-dvi    off          auto         on          
  1920x1080 (0x68)  138.5MHz +HSync -VSync +preferred
        h: width  1920 start 1968 end 2000 total 2080 skew    0 clock   66.6KHz
        v: height 1080 start 1083 end 1088 total 1111           clock   59.9Hz
  1920x1080 (0x5b)  148.5MHz +HSync +VSync
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock   67.5KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   60.0Hz
  1920x1080 (0x5c)  148.5MHz +HSync +VSync
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock   56.2KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   50.0Hz
  1920x1080 (0x69)  148.5MHz +HSync +VSync
        h: width  1920 start 2003 end 2047 total 2200 skew    0 clock   67.5KHz
        v: height 1080 start 1084 end 1089 total 1125           clock   60.0Hz
  1920x1080i (0x5d)   74.2MHz +HSync +VSync Interlace
        h: width  1920 start 2008 end 2052 total 2200 skew    0 clock   33.8KHz
        v: height 1080 start 1084 end 1094 total 1125           clock   30.0Hz
  1920x1080i (0x5e)   74.2MHz +HSync +VSync Interlace
        h: width  1920 start 2448 end 2492 total 2640 skew    0 clock   28.1KHz
        v: height 1080 start 1084 end 1094 total 1125           clock   25.0Hz
  1680x1050 (0x49)  119.0MHz +HSync -VSync
        h: width  1680 start 1728 end 1760 total 1840 skew    0 clock   64.7KHz
        v: height 1050 start 1053 end 1059 total 1080           clock   59.9Hz
  1280x1024 (0x4b)  108.0MHz +HSync +VSync
        h: width  1280 start 1328 end 1440 total 1688 skew    0 clock   64.0KHz
        v: height 1024 start 1025 end 1028 total 1066           clock   60.0Hz
  1280x960 (0x4c)  108.0MHz +HSync +VSync
        h: width  1280 start 1376 end 1488 total 1800 skew    0 clock   60.0KHz
        v: height  960 start  961 end  964 total 1000           clock   60.0Hz
  1152x864 (0x6a)   81.6MHz -HSync +VSync
        h: width  1152 start 1216 end 1336 total 1520 skew    0 clock   53.7KHz
        v: height  864 start  865 end  868 total  895           clock   60.0Hz
  1280x720 (0x64)   74.2MHz +HSync +VSync
        h: width  1280 start 1720 end 1760 total 1980 skew    0 clock   37.5KHz
        v: height  720 start  725 end  730 total  750           clock   50.0Hz
  1280x720 (0x63)   74.2MHz +HSync +VSync
        h: width  1280 start 1390 end 1430 total 1650 skew    0 clock   45.0KHz
        v: height  720 start  725 end  730 total  750           clock   60.0Hz
  1024x768 (0x50)   65.0MHz -HSync -VSync *current
        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock   48.4KHz
        v: height  768 start  771 end  777 total  806           clock   60.0Hz
  800x600 (0x54)   40.0MHz +HSync +VSync
        h: width   800 start  840 end  968 total 1056 skew    0 clock   37.9KHz
        v: height  600 start  601 end  605 total  628           clock   60.3Hz
  720x576 (0x65)   27.0MHz -HSync -VSync
        h: width   720 start  732 end  796 total  864 skew    0 clock   31.2KHz
        v: height  576 start  581 end  586 total  625           clock   50.0Hz
  720x480 (0x66)   27.0MHz -HSync -VSync
        h: width   720 start  736 end  798 total  858 skew    0 clock   31.5KHz
        v: height  480 start  489 end  495 total  525           clock   59.9Hz
  640x480 (0x59)   25.2MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock   31.5KHz
        v: height  480 start  490 end  492 total  525           clock   60.0Hz
  640x480 (0x67)   25.2MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock   31.5KHz
        v: height  480 start  490 end  492 total  525           clock   59.9Hz

Any idea why I have this issue?

BTW, thing that boggles me the most - same triple monitor configuration works fine in W7.

[chrisb]

I have some issues with triple monitor configuration on HD4000

It looks like you are running some version of Ubuntu 12.04? As far as I can see, the latest Intel driver in 12.04.02LTS was released in Feb 2012, which is pretty old. So you might want to try something more recent: either the Xorg Edgers PPA, Ubuntu 12.10 or the 13.04beta, or the Intel installer at https://01.org/linuxgraphics/

[nadrimajstor]

It looks like you are running some version of Ubuntu 12.04? As far as I can see, the latest Intel driver in 12.04.02LTS was released in Feb 2012, which is pretty old. So you might want to try something more recent: either the Xorg Edgers PPA, Ubuntu 12.10 or the 13.04beta, or the Intel installer at https://01.org/linuxgraphics/

You are correct. It is Ubuntu 12.04.2. Kernel and X version in 12.04.2 should be the ones from 12.10. I've tried Xorg Edgers PPA - no luck. Intel installer have issues with package names and fail to install on 12.04.2.

AFAICT looks like the problem resides in the kernel. I've tried with stock kernel 3.9 and thing are slightly better: It dose not hangs on boot (probably because resolution is automatically set to 1024x768 for all outputs). However raising resolution to monitor native values reproduce the error.

You've mentioned in previous posts that there are some resolution limitation - but exactly the same monitor configuration works fine in Win7 so I assume that hardware is ok.

Any idea is much appreciated.

[chrisb]

Any idea is much appreciated.

It sounds like a bug. I would report it as a bug at https://01.org/linuxgraphics/community/kernel and ask on the intel-gfx mailing list.

I've had problems in the past with mismatched kernel/xorg versions so it's usually best to try the same versions as upstream are using for testing.

Intel installer have issues with package names and fail to install on 12.04.2.

Ubuntu 12.04 is supposed to be supported by the Intel installer, so report it as a bug to Intel if it doesn't work. Make sure that you're on a fresh install though (if you've mixed 12.04 base with random PPA packages they will likely say it's unsupported)

[nadrimajstor]

It sounds like a bug. I would report it as a bug at https://01.org/linuxgraphics/community/kernel and ask on the intel-gfx mailing list.
I've had problems in the past with mismatched kernel/xorg versions so it's usually best to try the same versions as upstream are using for testing.

Ask on mailing list, report a bug. Got it. Thanks.

Ubuntu 12.04 is supposed to be supported by the Intel installer, so report it as a bug to Intel if it doesn't work. Make sure that you're on a fresh install though (if you've mixed 12.04 base with random PPA packages they will likely say it's unsupported)

ppa-purge usually take good care of removing PPA specific packages.

Yeah, Intel installer dose support 12.04 but it gets confused with 12.04.2 where some packages are named a bit different e.g. xserver-xorg-lts-quantal xserver-xorg-video-intel-lts-quantal ...

BTW, connecting all three monitors via HDMI works fine. And monitors with DVI inputs connected via HDMI adapters don't work on this board.
I've never encountered device that actually care if it is DVI or HDMI (This lead me to belief that same digital signal propagate no matter what connector type is (DVI, HDMI or DisplayPort))

[chrisb]

Yeah, Intel installer dose support 12.04 but it gets confused with 12.04.2 where some packages are named a bit different e.g. xserver-xorg-lts-quantal xserver-xorg-video-intel-lts-quantal ...

I'd still report it as a bug - there's not much point in supporting 12.04 and not 12.04.2, they're both LTS, it's the same version just with "major bug fixes".

BTW, connecting all three monitors via HDMI works fine. And monitors with DVI inputs connected via HDMI adapters don't work on this board.
I've never encountered device that actually care if it is DVI or HDMI (This lead me to belief that same digital signal propagate no matter what connector type is (DVI, HDMI or DisplayPort))

Are the monitors and cables DVI-D? DVI-I also carries an analog signal so it is possible for hardware to be DVI-I only.

Also for three identical (same pixel clock) monitors to work I have read that the connection type is also supposed to be the same - but I never understood if DVI-D and HDMI are considered "the same" in this context so you can mix them. http://en.wikipedia.org/wiki/Intel_H...ctive_displays

See also: Digital_Visual_Interface#Clock_and_data_relationsh ip

Ivy Bridge HD2500 and HD4000 chipsets are advertised as supporting three active monitors but many users have found that this does not work for them due to the chipset only supporting two active monitors in many common configurations. The reason for this is that the chipset only includes two PLLs; a PLL generates a pixel clock at a certain frequency which is used to sync the timings of data being transferred between the GPU and displays. Therefore, three simultaneously active monitors can only be achieved by a hardware configuration that requires only two unique pixel clocks, such as:

* Using 2 or 3 active DisplayPort connections. DisplayPort requires only a single pixel clock for all active connections, regardless of how many there are (this is not the case for non-active connections, which would require an extra pixel clock for each connection)

* By using two non-DisplayPort connections of the same connection type (ie. HDMI+HDMI) and same clock frequency (ie. connected to two identical monitors at the same resolution) so that a single unique pixel clock can be shared between both connections.