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Dell Display Manager can't see second monitor in Windows 10
I have Dell monitors: a U2515H, and a U2413. In Windows 7, Display Manager had a drop-down box at the top allowing me to select either monitor. In Windows 19 (which I've just installed), it's gone, so I can only change brightness for one of my monitors.
I downloaded the latest version from here but no difference (actually it told me my current version was newer).
Is there a software update in the works, or any manual fix I can do?
swamped1
234 Posts
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August 1st, 2015 15:00
DDM requires more than just detection of the monitor - it requires a reliable *two-way* communication channel to the monitor, where simply displaying something on screen only requires a one-way link. If you check the diagnostic log in DDM when you have a failed DP1.2 daisy-chain, I think you'll find both monitors are detected but one has a specific Windows error message that is passed by the display driver. The culprit will probably be from the 1st-gen U2413. This cannot be fixed by a DDM update.
Since 1st-gen DP1.2 monitors have known problems with DDC/CI, one thing to try is changing your physical configuration.
- Connect the U2515 directly to the AMD card, and *enable* DP1.2 in the U2515 OSD
- Connect the U2413 to the U2515, and *disable* DP1.2 in the U2413 OSD.
ghen
6 Posts
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July 31st, 2015 08:00
Dell Display Manager usually offers an update when one is available. But you can also check for the latest version manually. [SHFT] right-click on the task tray icon, and then select the "Check for new version..." item.
Cubbers
32 Posts
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July 31st, 2015 21:00
Thanks; I'm just looking for confirmation really that Dell are aware of this problem, in the hope that it will be fixed more quickly!
swamped1
234 Posts
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August 1st, 2015 11:00
I think you want to be looking for a GFX driver update, rather than a DDM update. Check your GFX vendor (Intel, or AMD or NVidia) to see if they have a newer driver available.
Cubbers
32 Posts
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August 1st, 2015 12:00
I've tested with HDMI, and DDM detects the second monitor with that. It just seems to be with extra monitors that are daisy-chained with DisplayPort 1.2. It worked fine in Windows 7. I'll run my second monitor using HDMI as a workaround while this remains not working.
Cubbers
32 Posts
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August 1st, 2015 12:00
Thanks for the suggestion, but I've got the latest display drivers, and neither the AMD Catalyst software or Windows itself has any problem detecting or using the second display. It's just Dell Display Manager that isn't working properly. Incidentally, DDM is the one and only app I've found to have problems since upgrading to Windows 10.
Cubbers
32 Posts
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August 1st, 2015 16:00
Thanks for your help, swamped. I did as you suggested, and DDM works that way. This is basically how I had it set up before, except with DP1.2 *enabled* on the U2413. Disabling DP1.2 there fixes the problem.
It may be that I enabled DP1.2 on the U2413 before upgrading to Windows 10 and didn't notice that DDM had stopped working. Unfortunately I can't go back to Windows 7 to check, but maybe it has nothing to do with Windows 10.
I confirmed that DDM can't talk to the U2413 at all in DP1.2 mode. I disconnected the U2515H and rebooted with just the U2413 connected with DP1.2 off. DDM worked. I switched DP1.2 on, and DDM stopped working. I saved a log at this point, which is here. I then turned DP1.2 off, and DDM started working again.
Connecting the U2515H to the U2413 (DP1.2 on), the extended desktop displays correctly, but DDM can only see the U2515H (and DP1.2 on/off on that one makes no difference).
So when you say "1st-gen DP1.2 monitors have known problems with DDC/CI" - does that mean the problem is with the monitor itself, and not something that could be fixed by the graphics card driver? Or is it worth pestering AMD for a driver fix?
ghen
6 Posts
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August 1st, 2015 17:00
I think swamped was suggesting a new graphics card driver before you mentioned that everything worked fine when using HDMI, but didn't work when using DP 1.2 daisy-chaining. But now you've confirmed the issue is with DP 1.2 communication. So it seems pretty unlikely a new graphics driver is going to make any difference.
swamped1
234 Posts
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August 1st, 2015 17:00
Dell would be better able to answer this question than me, but there are more than a few threads in this forum on problems with 1st gen DP1.2 monitors. The issue seems to touch every STmicro based monitor from the 2013 and early 2014 model years - U2413/U2713/U2913/U3014 - but it was not specific to Dell, it occurred with NVidia and Intel as well as AMD drivers, and it seems to have been cleared up in newer models- as you see with the U2515.
I don't know if the problem is/was with the monitor firmware or the GFX driver software (DP1.2 was a new spec at the time), but its probably the former or it would have been fixed by now. So: No, I'm afraid you aren't likely to ever see a solution in the form of an AMD driver fix.
Cubbers
32 Posts
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August 1st, 2015 18:00
OK ta. Not a problem for me with my configuration, but it's interesting to know reasons why it wasn't working. It also helps explain why DP1.2 is *optional* in the menus - was wondering about that!
I think I'll stick with HDMI for my second monitor, since it gives me the extra option of simply turning the first off if I ever want to just use that one for some reason.