11-13-2019 11:28 PM
I am trying to connect 2 external HDMI monitors to my L580 Thinkpad.
To do so I am using the normal HDMI port for one Monitor and a generic USBC to HDMI adapter for the second monitor.
But whenever I connect the HDMI Cable to the usbc adapter the display just switches off the internal HDMI Port and shows the image on the adapter HDMI port.
Is this the expected behavior ? Does the L580 natively only support 1 external screen ?
Solved! Go to Solution.
11-14-2019 06:03 AM
Hi Schrimp88! Welcome to our forums community. Your laptop can work with a maximum of two external displays. With a maximum resolution of 4096 x 2304 at 60Hz through the USB-C and a maximum of 4096 x 2160 at 30Hz through the HDMI.
Just to clarify, whenever you connected the second monitor that is connected through the USB-C port, the first monitor turns off? And it has USB-C to HDMI adapter going to the external monitor?
Try running the update using the Vantage app, install all available updates especially the graphics card update. You may also manually update from our website: https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-l-series-laptops/thinkpad-.... Let us know if the issue persist.
11-16-2019 10:44 AM
I installed all available updates through Vantage app. Actually Bios, Intel Management engine and USB Docking utility got updated.
Unfortunaltely the issus still persists, as soon I plug in the USBC Dock, the native hdmi port is switched off.
Actually I tried the same thing on my T570 Model and everything works like it should.
Any suggestions appreciated.
11-18-2019 07:11 AM
Have you tried bypassing the docking station and check if the issue is the same? Could you also send to us the current Windows 10 version running on y our computer? Try also checking if there pending updates.
11-20-2019 12:32 PM
I have done all pending updates which included a Windows update from 1809 to 1909.
after doing that I got a notification, that said, a new intel graphic toolkit was installed.
I was opening the toolkit full of hope, that I can find some setting like "enable support for 2 external monitors ... " but nope.
disapointed a walked through the available settings eventually plugging in and out the usbc dock, and suddenly both 2 external and 1 internal screen was operational. Then I closed the tool and plugged of / on the 2nd screen again ... resuting in the behavior as before (hdmi switched off usbc switched on)
Then I though: "oh, i have to start the intel graphics toolkit before I plug the second monitor .. " ... so tried that, but nope ... same behavior as before ...
Finally it turns out, that I have to open the submenu in the tool in which manages the dektops (not the monitors can be managed), then, and only then I plug the 2nd monitor, the monitor will be detected corectly and I can work on to external monitors.
I tend not to call this a fix, but only a dirty workaround which probably disapear on the next driver update.
would be great if someone at lenovo could try to replicate this behavior and put some pressure on Intel to provide a real fix for that.
11-21-2019 01:10 AM
This morning the recepy above worked, after the computer fell into sleep and woke up again, the recepy does'nt work anymore.
Also reboot does not recover ...
So I am back at start ....
11-21-2019 07:32 AM
Base on the manual, if you are using the USB-C, you can only connect to USB-C to VGA or USB-C to Display Port. It can not connect 2 HMDI at once because it is connected to the integrated graphics card.
You can refer to this link: https://download.lenovo.com/pccbbs/mobiles_pdf/l480_l580_ug_en.pdf, page 5.
11-22-2019 03:02 AM
ah, ok based on the attached chart (which is not included in the linked manual, by the way) one can clearly see that that the switch PS8337 routes DDI1.2a Port1 to either HDMI or USBC Rear. Which makes clear why USBC Rear and HDMI cannot used as Display interface at the same time.
However one can also see that the front USBC port can act as an interface to DDI1.2a Port2. Assuming that the red dashed line is actually valid. Actually I was not really aware that a second USBC port extists, as it is kind of hidden in the docking connector ...
This explains why I can just hook up my HDMI to USBC adapter to the front USBC port and things (not really magically) just work as expected. Even with a 2nd HDMI monitor connected.
The only remaining question is why the rear port occasionally worked before, when opening this intel tool .... probably I just ocasionally connected the adapter to the front port by accident .. which I do not really think, because I tried this too often, and I was not even aware that it is a valid port ... my suspicion is that there is a potential option (from Hardware) that one DDI1.2a port is driving multiple screens, but it is not really supported by the driver ... and with some glitch in the intel tool it can be enabled under specific cirumstances.
However I think this is solved for me. Many thanks for the fast and responsive support on this isse.