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October 5th, 2017 01:00
M4600 problems with extended displays
I've been messing with the m4600 to try to get it to work with extended monitors with some success but no where close to what I was looking for.
Ideal setup: 2 monitors, 1 via display port and 1 via vga
Problems I ran into with no solutions:
1. When connecting using the display port, I get a no signal from the monitor and it turns off the laptop lcd. How is this possible? I'm playing with a 4K monitor (with display port) but that shouldn't be the issue? (or is it?) Side note, does the AMD firepro M5950 (firegl) support 4K? Does the display port support 4K?
2. Cannot do 2 monitors extended with its own LCD. I could only do 1 vga OR 1 hdmi. Can't even do 1 display port, which would be great (and if it could do the 4k monitor setup)
Tested, monitors are fine. Cables are fine. m4600 seems to be fine.
Reference: m4600 with 1GB AMD firepro M5950
Any suggestions are greatly appreciated. Thanks.
jphughan
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14K Posts
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October 5th, 2017 07:00
According to this article, since you have discrete graphics in your system, you should be able to achieve up to dual 4K displays on the dock. Are you using the latest available drivers from support.dell.com or AMD? And what specific 4K display do you have? Some older 4K displays only work in what's called MST (multi-stream transport) mode -- basically it was a hack for when single display controller chips couldn't handle a 4K signal, so the display was actually set up to present itself to the system as 2 smaller displays. The problem is that I'm not sure the M4600 supports DisplayPort MST (required to drive "2 displays" out of a single connector), and even if it did, that might prevent you from running another display alongside it; I don't know what the M4600's maximum total number of displays is. Newer 4K displays use SST (single-stream transport) and work just as you'd expect a display to work.
I'm not sure why the internal panel would be disabling when the other display is powered on, except perhaps the PC thinking that a signal is reaching that display and running it in single-display mode. You can try the Fn key to cycle your display configuration to see if that restores an image to at least your internal LCD, which would allow you to see what the PC thinks is there.
nomanmail
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October 5th, 2017 09:00
Monitor is LG brand 4k, released 2016/2017.
I was testing it more on hdmi and only got 1080 and at 30hz. WAY below what it should be capable of doing.
I did get the display port to "display" but at 800x600. I eventually lost it some how and back to the no signal message. I've read something about display port needing to be 1.2 to run 4k.
Lost for solution here and continuing to see what else I can dig up.
fyi, article link got a 404 not found
jphughan
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October 5th, 2017 12:00
I'm not sure why even that second link isn't working for you. I just retried it and it works fine for me. If you right-click it, select Copy Link Location (or whatever your browser calls it), and paste it somewhere, what are you seeing? But basically, if you haven't already, try using DisplayPort 2 rather than DisplayPort 1 for your 4K display. I've also printed that page to PDF and attached it below if you still can't get to that page.
You really can't look behind your display to post the exact model of LG display you're using? The other suggestion I was going to make was to make sure your display is set for DisplayPort 1.2 mode. That's required for 4K @ 60 Hz, but it's sometimes disabled by default for compatibility reasons.
[View:/cfs-file/__key/communityserver-discussions-components-files/3518/E_2D00_Port-Plus-and-4k-displays.pdf:550:0]
nomanmail
19 Posts
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October 5th, 2017 12:00
Reference: m4600 with 1GB AMD firepro M5950
With a dedicated video card I thought it would be sufficient (?)
But I have read that the display port needs to be 1.2 to support 4k monitors (fyi, using a LG model released 2016/2017). The specs sheet doesn't say so I'm looking around.
Are you referring to Fn key+f5? to toggle screens?
Fyi, article link show a 404 not found
I think I'll need to do a lot more digging to see what is going on. Accepting all suggestions and inputs. Thanks again.
jphughan
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October 5th, 2017 12:00
Unfortunately brand and release date don't allow me to look up specs. Do you have a model name/number? It would usually be printed on the back of the display. 4K @ 30 Hz on HDMI isn't too surprising since 4K @ 60 Hz over HDMI requires HDMI 2.0, and it's possible that your display and/or PC only support HDMI 1.4, which maxes out at 4K @ 30 Hz. There are many displays on the market that can't be driven at their native resolution over HDMI. In the earlier days of HDMI, the early 2560x1440 displays would only accept 1080p over HDMI, for example. The reason is that at any given time, DisplayPort has always supported higher resolutions than HDMI, and vendors don't wait for the HDMI spec to catch up before releasing their first display models that support those higher resolutions. Display models released later, after the HDMI spec has caught up, typically accept their native resolution even over HDMI. But again, the system itself ALSO has to support that resolution on HDMI, and your M4600 is definitely too old to have HDMI 2.0.
Not sure what happened with that earlier link, but here it is again: www.dell.com/.../e-port-plus-and-4k-displays