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E6440 Catalina 10.15.4 with docking


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I am trying to get display working through the docking replicator  (DisplayPort).  The OS recognize the external monitor and can identify the monitor model.  But the monitor is not receiving signal and after a few seconds, it goes into power safe mode. 


Attached is the debug file.  


Hope some one can provide pointer or assistance.


Thank you.


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Hi Herve,


Thank you for the pointer.  I've read through your forum thread and here is my understanding.  Please let me know if I am not correct.  From the original "AppleIntelFramebufferAzul", This the hex output that I got


0600260A 01030303 00000002 00003001 00006000 00000060 D90A0000 D90A0000 00000000 00000000 00000800 02000000 30000000 01050900 00040000 87000000 02040900 00040000 87000000 FF000000 01000000 40000000 0F000000 01010000 04000000 00000000 0E000000 00000000


Which tell me that port5 should be DP and port6 should be DP.  But base on my "ioreg -l" output I got the following.


"connector-type" = <02000000>
"port-number" = 0

"connector-type" = <00080000>
"port-number" = 5

"connector-type" = <00040000>
"port-number" = 6


So it looks like it's been inject by Clover ?  I can use the hdmi port from the laptop without issue.  

If using Clover, how can I change port5 to use DP instead of hdmi ? Can I increase the graphics card RAM from 1536 to 2048 via Clover ?


Thank you.

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Your Clover config does indeed apply the expected and required patches to IOReg device located @00020000 (i.e. the IGPU). Open up your config file in Clover Configurator, go to Devices tab, click on Properties and select device PciRoot(0x0/Pci(0x2,0x0).


In the right section, you'll see that HDMI connector-type 00080000 is applied to FB@1/port #5 and revised DP connector-type 00040000 is applied to FB@2/port #6. This is the expected config to activate and support HDMI output + DP output. So yes, HDMI will work if you plug an HDMI display into the laptop's HDMI port for instance. Same should be applicable for DP outputs out of an E/Dock.


With regards to VRAM increase to 2GB, the patching guide also explains what to do on the matter and in that same properties section as above, you should notice a 1st line starting with a #. # character means that the line is commented out and that it actually corresponds to the VRAM increase patch. Uncomment the line by removing the # character and you'll obtain 2GB VRAM.



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Hi Herve,


Thank you for the pointer.  I was able to increase the vRam to 2048 after uncommenting the line.  

Base on the config.plist file, port@2 already set for DP and I should get output.  Unfortunately, macos detect everything but its not sending any signal to the monitor. See the screenshot below.


If I use a DP->HDMI adapter on port@2 (port replicator DP port), I do get picture on the monitor.  Is there some option I need to tweak to make DP work ?  Also, the monitor is a 4k monitor.  Is there option to make macos support the 4k resolution ?  Right now the HDMI resolutions are limited to 2560 x1600.


Thank you

Screen Shot 2020-04-21 at 3.45.22 PM.png

Screen Shot 2020-04-21 at 3.45.32 PM.png

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Hi All,


After fiddling with this issue on and off for the last few weeks.  Finally able to resolve it. (for the most part).  The resolution on my 4k monitor (Acer ET322QK) is OK, but not perfect.  

It turns out that MacOS Catalina sends  YPbPr signal to my monitor and it makes the 4k screen looks blurry and with limited resolution support via HDMI cable.   With DP connector,  my monitor does not even detect the signal.


I stumble upon the following article and was able to get MacOS to output RGB signal to my monitor.  I was able to get 1920x1080 with HiDPi support via the HDMI and DP output. Anything higher than 1920x1080, the fonts becomes blurry again. ( I can go all the way up to 3840x2160, but it's just not worth it)




Hope this helps someone who have the same issues as I have.





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