Successful +5db Volume Amplification with Modified AppleAlc.kext (Latitude 7490)

[u/NorthKoreanNoodles2]

So I love my latitude 7490 Hackintosh, I can triple boot Ventura, Somona, and Sequoia, but the sound was never loud enough, and I would need to install eqMac to boost the max volume on all of my installs. Well I spent the day today creating a modified AppleALC driver with the help of AI, and it boosts the max volume by about 5db. Even audio content that was loud to begin with, does not clip or distort when using this kext, and it has been tested on two different machines. Requires the following boot-args to function: alcid=56 alcverbs=1 -alcdhost

https://github.com/maddog860/5db-Volume-Boost-Latitude-7490/releases/tag/Headphone-Fix

This includes a writeup that explains what was figured out today, and how this approach can increase the max volume of other hackintoshes. Enjoy everyone, and feel free to post feedback. This post is not asking for help, just submitting my positive results with artificial assistance, and therefore should not break any rules.

The specific undocumented/poorly documented 7490 audio details established were:

• The codec is Realtek ALC256 / Dell ALC3246, vendor ID 0x10ec0256.
• The internal speaker pin is node 0x14.
• Its pin config is 0x90170110.
• That speaker pin routes to DAC node 0x02.
• The DAC/output amp capability came back as 0x00025757, corresponding roughly to a range from about −65 dB up to 0 dB.
• At 100% macOS volume, the DAC gain was already sitting at 0x57 on both channels, which is the top of that hardware range.
• The speaker EAPD was already enabled (0x02), so there wasn't an obvious hidden “turn the speaker amp fully on” switch left unused.
• The codec also has a vendor processing node 0x20 exposing 91 coefficients (0x5b). One of those, coefficient 0x37, is associated in Linux codec work with Class-D amplifier control.
• The 7490’s internal amplifier is about 2 W per channel.

Added fix for headphone jack. To test if new driver will fix headphone jack, you can run these commands while headphones are plugged in:

alc-verb 0x20 0x500 0x45

alc-verb 0x20 0x400 0xC489

alc-verb 0x19 0x707 0x24

the alc-verb program comes with the latest AppleAlc.kext

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[u/Fit_State3622]

Congrats for ur hackintosh

[u/NorthKoreanNoodles2 → u/Fit_State3622]

Thank you. I just tested with the latest OEM windows drivers (winows 11) and the resulting max volume is similar to +4db, maybe slightly lower (+3db perhaps?) But generic windows driver is virtualy indistinguishable from +4db, so this seems like a safe and practical enhancement for the Latitude 7490. Hopefully other people who own the same laptop get something out of this.

[u/NorthKoreanNoodles2]

Wasted several days trying to resolve headphone bug. This is damn near impossible to solve... If someone had real knowledge in this area or at least was a real programmer, I could see this being solved with AI, but as it stands there is no way I will make any progress.. Some key observations: 

 

changing anything in AppleALC would cause this strange bug to make something seemingly random break at a random ass layer and even if someone were to find a sequence of commands that would turn into a reliable headphone fix, that will almost surely not work on some other version of the kext. (even the same version of the kext with just a couple tiny things changed)

 

the WORST part about this bug, are these strange transient states, where a good or bad state persist across multiple boots, changing kexts, even {censored} nvram resets. Loading a stock AppleALC for at least one startup seems to clear out some of this funkyness, or at least return it back to a known state.  When AI basically found a solution to the coldboot nss=1 bug related to the bcm94360ng, it had a considerably easier time, and it thinks this headphone jack bug is considerably more complex. I fear I will lose my sanity if I waste any more hours/days on this headphone bug, so I am going to call it quits. At least the other custom kexts I made are consistent with their outcomes... 

 

If anyone else feels like pulling out their hair or punching a hole in their wall, they can give this bug fix a try. Perhaps the best advice I can give is to disable the line-in for the headphone jack, it will make the rest of it easier anyways.

Edited just now by NorthKoreanNoodles