[GUIDE] General Framebuffer Patching Guide (HDMI Black Screen Problem)

[deeveedee]

This is very interesting... I started with the defaults and I was not able to make DP work under BUS ID 0x05. So I started to play with other values and 0x01 was the Bus Id that worked. Since then, I haven't found any issue and I am able to have up to 3 displays working simultaneously.

Just to confirm, you are using BusID 0x01 with DP? I'm asking, because that is contrary to the supposedly valid DP BusID's specified in Post #1 of this thread. I have been using BusID 0x01 with DP->DVI adapters in my HP EliteDesk 800 G4 Mini as noted here, but I thought that was because I was using DP->DVI adapters.

 

[Ashrey]

Hi, I´m running Catalina 10.15.6 on a Gigabyte H470M DS3H, it works pretty fine, but I can´t get accelerated graphics to work. Anyone can help, please?

I got igpu acceleration working successfully

 

[checotrevi]

Just to confirm, you are using BusID 0x01 with DP? I'm asking, because that is contrary to the supposedly valid DP BusID's specified in Post #1 of this thread. I have been using BusID 0x01 with DP->DVI adapters in my HP EliteDesk 800 G4 Mini as noted here, but I thought that was because I was using DP->DVI adapters.

Yes, that is correct. According to the post:

• DisplayPort is the most flexible. BusIDs 0x02, 0x04, 0x05, 0x06 are permitted. Any of these values should work on any motherboard. These values apply to VGA as well.

i tested all ports and none worked. I thought it was because i was using a DP-HDMI adapter, but when i tried Bus Id 0x01 it worked.

This is a screen shot of the connectors with DP active on Bus id 0x01:

and this picture shows the connector with the adapter:

So not sure how/where they found out DisplayPort cannot be Bus id 0x01.

 

[deeveedee]

Yes, that is correct. According to the post:

• DisplayPort is the most flexible. BusIDs 0x02, 0x04, 0x05, 0x06 are permitted. Any of these values should work on any motherboard. These values apply to VGA as well.

i tested all ports and none worked. I thought it was because i was using a DP-HDMI adapter, but when i tried Bus Id 0x01 it worked.

So not sure how/where they found out DisplayPort cannot be Bus id 0x01.

Ok. You are using a DP->HDMI adapter. BusID 0x01 is valid for HDMI. It would appear that the BusID must be selected based on the converted connector type and not the connector type on the graphics card or motherboard. In other words, since I am using a DP->DVI adapter, my valid BusID's are for DVI. Since you are using DP->HDMI adapter, your valid BusIDs are for HDMI. The fact that we both have DP connectors does not determine our BusID since we are using adapters.

Post #1 clearly indicates that the directions/guidance change when you are using adapters. Since neither of us is using DP->DP, we cannot say whether the BusIDs for DP are valid or invalid. Until hearing from someone who has evidence to the contrary, I'm assuming that anyone who uses DP->DP cables without adapters must comply with the BusIDs listed in Post #1.

What is abundantly clear is that anyone asking for help with their UHD graphics MUST indicated whether they are using adapters (e.g. DP->HDMI).

 

[safehans]

Thanks for replying. I'm guessing it's something to do with adapters. For me with BusId 5 and Pipe 18 DisplayPort cable works fine but Displayport to DVI cable doesn't. I noticed you're using a Displayport to HDMI adapter.

Your build look nice and you should post it in completed builds!

Hi Safehans...

This is very interesting... I started with the defaults and I was not able to make DP work under BUS ID 0x05. So I started to play with other values and 0x01 was the Bus Id that worked. Since then, I haven't found any issue and I am able to have up to 3 displays working simultaneously. Interesting that you have different values on same card... but if this works for you, leave it as it is.

In regards to the flags, I can't remember where I saw those values but they seem to work pretty good. Same thing with the pipe.

My first build was done using Clover, but I was having a lot of kernel panics on my boot and never felt confortable with this bootloader besides that NVRAM was not working at all. So I decided to move to OpenCore 0.6.0 and after cleaning it up, i am very very happy with the result. OpenCore seems to be a more clean and straight forward solution. No panics, no errors, EVERYTHING works as it should. All USB ports, Ethernets, Audio, Bluetooth, WiFi, video, sleep/wake, NVRAM, etc., etc.

I can tell you, it boots pretty much like a Mac, i was able to hide the bootloader menu and when you turn it on, it goes straight to the apple logo.

Yesterday i was able to install Catalina update without any issue. It took longer than the typical update though (i thing this one was a big one).

View attachment 486849

 

[checotrevi]

Thanks for replying. I'm guessing it's something to do with adapters. For me with BusId 5 and Pipe 18 DisplayPort cable works fine but Displayport to DVI cable doesn't. I noticed you're using a Displayport to HDMI adapter.

Your build look nice and you should post it in completed builds!

I will... maybe this weekend. . cheers!

 

[checotrevi]

Ok. You are using a DP->HDMI adapter. BusID 0x01 is valid for HDMI. It would appear that the BusID must be selected based on the converted connector type and not the connector type on the graphics card or motherboard. In other words, since I am using a DP->DVI adapter, my valid BusID's are for DVI. Since you are using DP->HDMI adapter, your valid BusIDs are for HDMI. The fact that we both have DP connectors does not determine our BusID since we are using adapters.

Post #1 clearly indicates that the directions/guidance change when you are using adapters. Since neither of us is using DP->DP, we cannot say whether the BusIDs for DP are valid or invalid. Until hearing from someone who has evidence to the contrary, I'm assuming that anyone who uses DP->DP cables without adapters must comply with the BusIDs listed in Post #1.

What is abundantly clear is that anyone asking for help with their UHD graphics MUST indicated whether they are using adapters (e.g. DP->HDMI).

Makes sense... but I thought they were fixed. Anyway, I will be able to test it once i get a monitor with DP connector.

 

[deeveedee]

Makes sense... but I thought they were fixed. Anyway, I will be able to test it once i get a monitor with DP connector.

Just curious - if you change your DP connector type to HDMI, do your displays still work correctly? With my DP->DVI adapters, I need to set my connector types to DVI (even though my motherboard has DP ports) or my displays do not work properly. I would think that when using DP->HDMI adapter, you would need to set your connector type to HDMI.

Thanks for satisfying my curiosity.

 

[checotrevi]

That's exactly what I was trying to understand. I changed Framebuffer-Conn0-Type from DP (0x00040000) to HDMI (0x00080000) and the display is still working after reboot.

 

[deeveedee]

That's exactly what I was trying to understand. I changed Framebuffer-Conn0-Type from DP (0x00040000) to HDMI (0x00080000) and the display is still working after reboot.

Good to know that it behaves as expected. For me, using connector type DP when using DP->DVI adapters does not work. For you, it appears that both DP and HDMI are acceptable connector types when using DP->HDMI adapters. Thank you for checking.

EDIT: @checotrevi - I may have been too quick to respond. As I posted here, I needed to reboot a few times to fully observe the effects of my connector type change. I'm not sure about your configuration, but it would be best for you see if conn type HDMI still works after a few power cycles.