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E7440 4K monitor only 1080p


patriciocs
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I have a fully working E7440 laptop with Mojave, but I have one issue when I try to use my 4K monitor Samsung U28E590. I enabled HiDPI and installed RDM in order to select resolutions higher than 1920x1080, however it doesn't matter what resolution I choose over that 1920x1080 I never get the real resolution but a blurry fake one. I tried with my monitor native resolution (3840x2160) and many others with no luck.

 

It looks like OSX is just faking the resolution and keeps just sending 1920x1080. I connected my laptop to monitor using a HDMI cable.

 

Does anyone had experience using a 4K monitor with an E7440 laptop? Is it possible to use a retina resolution with this setting?

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I have not personally test this since I don't have any 4k monitor but read some users were able to achieve it for HD4400 by raising the DVMT pre-alloc from 32mb(default on this model) to 128MB in the BIOS.

Since you can't access this setting from Dell's BIOS, you'll need to use the EFI shell to accomplish this.

See my guide here

After that, you'll need to disable the 9mb cursor patch and enable or add this 48mb cursor patch to your Config file under kexttopatch.

Use PlistEditor or Xcode to add

Spoiler

 

<dict>

<key>Comment</key>

<string>Enable 128MB DVMT-prealloc, 48MB framebuffer, 48MB cursor bytes, 0x0a260006</string>

<key>Disabled</key>

<false/>

<key>Find</key>

<data>

BgAmCgEDAwMAAAACAAAwAQAAYAA=

</data>

<key>InfoPlistPatch</key>

<false/>

<key>Name</key>

<string>AppleIntelFramebufferAzul</string>

<key>Replace</key>

<data>

BgAmCgEDAwMAAAAIAAAAAwAAAAM=

</data>

</dict>

<dict>

<key>Comment</key>

<string>Enable 9MB cursor bytes, 0x0a260006</string>

<key>Disabled</key>

<true/>

<key>Find</key>

<data>

BgAmCgEDAwMAAAACAAAwAQAAYAA=

</data>

<key>InfoPlistPatch</key>

<false/>

<key>Name</key>

<string>AppleIntelFramebufferAzul</string>

<key>Replace</key>

<data>

BgAmCgEDAwMAAAACAAAwAQAAkAA=

</data>

</dict>

 

 

or with Clover Configurator, add this

Name:     AppleIntelFramebufferAzul

Find:        0600260A 01030303 00000002 00003001 00006000 

Replace: 0600260A 01030303 00000008 00000003 00000003 

Comment: Enable 128MB DVMT-prealloc, 48MB framebuffer, 48MB cursor bytes, 0x0a260006

 

Don't forget to disable the "Enable 9MB cursor bytes, 0x0a260006" patch

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Thank you very much for your advice @Jake Lo but sadly I get a kernel panic when I enable 128MB. I think I followed correctly the steps in your guide (however I found some issues with Universal IFR Extractor with "Protocol: Unknown" instead of "Protocol:UEFI" error). It looks like the variable is at address 0x255 in my BIOS but if I change the value of this OSX doesn't boot.

 

Attached is my config files and the files I used in your guide in case you could take a look.

DellE7440_4K.7z

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Can use this partial Opencore EFI to modify DVMT as well. Add the EFI folder to an EFI partition on a USB Thumb Drive. 

Hit F12 at boot, choose boot UEFI on thumb drive. After it loads, select modGRUBShell.

At prompt grub>  

setup_var 0x255 0x4 enter. (Set DVMT @ 0x255 to 0x4)

setup_var 0xC8B 0x0 enter  (Set CFG Lock @ 0xC8B to 0x0) this one may not be necessary, but turning CFG Lock off on mine didn't break anything either.

Then just type reboot & enter.

 

 

DVMT and CFG Lock locations are from Jake Lo's Guide. :)

EFI.zip

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