Remove 165 MHz pixel clock limit; 4K over HDMI; overclocking

[floris497]

Nvidia web drivers for OSX 10.10.5? Can you offer any pointers or links? Maybe there is a way to disable the discreet graphics altogether to test just the HD4000? More research required.

This is all starting to make a lot more sense thanks damsel and floris497. I couldn't find any web drivers for this specific card for OSX, I was able however to find a slight increase using switchers 3456x1944@24hz almost the full 4k resolution (no audio) using the passive mdp -> hdmi adapter.

I have a mini-displayport to displayport cable coming soon, and once I can test that I'm hoping that the Nvidia card will allow it to go much higher than the 165hz. It looks like I might not have to use the USB3 4k adapter at all, and that would be good to support the clamshell mode too (which doesn't work with the USB displaylink adapters).

Thanks again.

http://www.macvidcards.com/which-driver-should-i-install-for-my-new-gpu.html

Hope that works!

 

[jthunder]

This is like a good mystery book! Tried installing the latest web driver 03f01 and it detects the NVIDIA card in the menu, but still no luck at getting switchresx to push past my previous resolution, and still appears to be limited to the 165mhz.

My USB3.0 displaylink adapter came (based on the DL5500), and getting it connected was a snap, using the display port 1.2 port, OS X detected and was able to set the resolution to the full 3840x2160@30hz, and text now looks sharp at the full resolution. However when testing 4k youtube videos at full screen it is noticeably choppy, due to the CPU having to process the video for the USB adapter. The same video on the HDMI port is smooth due to the processing done by the GPU instead.

So now that I understand a bit more about all the technology involved, it seems that the GT650M is a kepler card and should in theory support at least 4k@30hz. Now to try to figure out what the pixel clock limitation is, as it really appears to be artificially enforced in software somewhere.

Trying to disable the Nvidia card to see if the HD4000 integrated chipset doesn't work either as using the external display requires it to be enabled (at least with gfxCardStatus).

Have you guys tried identifying where the pixel clock rate is set for the nvidia discreet graphics chips?

 

[floris497]

It has been patched in the past, but i have no idea if the patch still works. Probbably not since it dates back a few years. If you where to change the kext the signature would be invalid. This is a problem because unsigned kext files won't work on 10.9.3+ so you need to disable that.. This can be done by setting a boot-arg meant for kext developers.

I can try to find out a little more about how to patch this, but i'm currently quite busy.. I've read that is was just a value you need to change instead of a deducated checking function.

I would have to google this.

 

[jthunder]

I took a look at the driver that 10.10.5 is using and found the string that was being patched in the original kext. I patched that manually and copied it over the original. I also disabled kext signing in nvram and rebooted. The laptop boots fine but still can't get past the 165hz. I created a patch here for the original patching utility - https://github.com/mlinton/mac-pixel-clock-patch/commit/7861a277652c65c93c34a3c0945daebada8aec5a

When using the nvidia utility OS X loads a slightly different kext `com.nvidia.web.NVDAGK100HalWeb`

Going to bang around some more with this...

 

[floris497]

I took a look at the driver that 10.10.5 is using and found the string that was being patched in the original kext. I patched that manually and copied it over the original. I also disabled kext signing in nvram and rebooted. The laptop boots fine but still can't get past the 165hz. I created a patch here for the original patching utility - https://github.com/mlinton/mac-pixel-clock-patch/commit/7861a277652c65c93c34a3c0945daebada8aec5a

When using the nvidia utility OS X loads a slightly different kext `com.nvidia.web.NVDAGK100HalWeb`

Going to bang around some more with this...

use the included file, can you report to me if this patch actually works?
if so i will be updating my fork on github with the nvidia web drivers as wel, maybe both web and osx drivers. needs some testing. i have no card that is limited to 165Mhz

This will patch the web driver, i have no idea if it is the same for mobile as for desktop.
this patch was quite simple to make, as you might have experienced yourself.

make sure you use the patched version, so if you patch native drivers use the native drivers,
if you patch the nvidia web drivers use those, can be selected in the menu or is system prefs.

 

[jthunder]

Cool thanks, it didn't work but here's a few things. There was some typos in the script - I've attached a corrected one.

The other thing is that after installing the web drivers I have what looks to be three drivers installed in the /System/Library/Extensions (see screenshot). Possible it loads all the drivers and then picks the one on boot that it needs?

When I run kextstat I can only see the com.nvidia.web.NVDAGK100HalWeb loaded (see kextstat.txt).

I think this means that only. If I take a look at the AGK file it has the same code pattern from the patch. I applied the patch to the AGK file and no luck either.

Any ideas?

It is possible that the "passive" thunderbolt 1.1 -> HDMI adapter is the bottleneck (maybe only HDMI 1.1 or 1.2?). If this was the case would SwitchresX show invalid? And this would make all of this driver hacking unnecessary - arg!

Cheers.

 

[floris497]

What machine did you have again? Maybe it tries to use your Intel gpu.. I have no experience with how OS X handles multiple gpu's.. Did you look into the executible to change it, and dis the checksum change? Try to patch the loaded kext files, you can see it in system information.

I have no idea how else to fix it..

 

[jthunder]

Its a mid-2012 15" MBP, the one with the GT650M and the Intel HD4000.

Tried to patch the loaded kext (thanks for the tips on that one), with no luck. Checksum change?

Anyway I guess I have to wait till the other DP cable or active-hdmi dongle gets here... To be honest the 3456x1944x24 resolution is not bad at all, just something about not having the extra 2" around the sides, and 6hz gets to me.

Thanks again for the help.

 

[jthunder]

Ok, update.

Please disregard all the other hackery that my previous posts included. I got the monoprice active displayport 1.1 to HDMI ACTIVE cable, plugged it into a newly installed Yosemite installation and bam, 3840x2160@30hz natively. No unlocking pixel-clocks, no kext hacking, no NVIDIA web drivers, no switchresX, just works. Not 60hz, but stable clean native resolution.

JT

 

[xequtor]

works also with El Captain 10.11, tested on Mac Mini late 2012, HDMI 2560x1440 50Hz, Accell Mini Dp 1.1 To HDMI 1.4 Active Adapt 2560x1440 60Hz, over HDMI works only with max 50Hz which is sufficient, I had to remove SwitchregX incl. stuff under ~/Libary and reinstall to make it work.
sudo perl -i.bak -pe '$before = qr"\x0F\x85\xDE\x03\x00\x00"s;s/$before/\xE9\xC5\x03\x00\x00\x90/g' /System/Library/Frameworks/IOKit.framework/Versions/A/IOKit
sudo touch /System/Library/Extensions

or here
https://github.com/Floris497/mac-pixel-clock-patch

 

[secmp]

hey,

when I tried to patch the IOKit it read something like
the kit's path was "replaced". Does this mean the IOKit is patched?

 

[aeolusmusic]

I ran this patch on my hackintosh (yosemite, i7, Geforce 970, msi x99sli) and now when I boot from clover the computer reboots before I even get to the apple logo. Is there a command I could use to undo/default the settings?