HP Models with Realtek ALC295 codec - Linux Audio Problem

[robertjjoynt]

There is a problem with the audio when running Linux on HP models that use the Realtek ALC295 codec. This problem is being reported by multiple users, and not only with different HP models, but also DELL and others (see links below). The problem is that a crackling sound occurs when using headphones. This problem occurs when booting directly into Linux from power on, but doesn't occur if the computer is first booted into Windows 10 and then Linux  (in this case the audio works fine, but the problem comes back if a suspend and resume is done). 

The Linux kernel supports the ALC295 codec. I am in contact with a Linux kernel programmer who has advised me to contact HP as this may be a vendor-specific issue. I have collected some data on the /proc values which show the differences between the audio hardware in the working case and non-working cases (as instructed by the Linux kernel programmer). I am presenting my findings below in the hope that this may be useful and in the hope that a fix can be provided.

Regards, Robert.

Links for the issue:

Ubuntu Bug Report::

https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1648183

Linux Kernel Bug Report:

https://bugzilla.kernel.org/show_bug.cgi?id=195457

Cases:

I compared data for three cases as follows:

• Working Case: Boot into Linux after booting into Windows 10. Audio works fine.
• Non-working Case 1: Boot into Linux from power on. Crackling audio on headphones.
• Non-working Case 2: Boot into Linux after booting into Windows 10. Then suspend and resume. Crackling audio on headphones.

Findings:

The proc differences between Working Case and Non-Working Case 1 consists of 8 Coeff values (no other differences) as follows:

$ diff proc-working.txt proc-nonworking-1.txt
265c265
<     Coeff 0x08: 0x6a0c
---
>     Coeff 0x08: 0x6a8c
270c270
<     Coeff 0x0d: 0xa02f
---
>     Coeff 0x0d: 0xa023
273c273
<     Coeff 0x10: 0x0120
---
>     Coeff 0x10: 0x0020
312c312
<     Coeff 0x37: 0xfe15
---
>     Coeff 0x37: 0xfe05
326,327c326,327
<     Coeff 0x45: 0xd689
<     Coeff 0x46: 0x00f4
---
>     Coeff 0x45: 0x5289
>     Coeff 0x46: 0x0af4
330c330
<     Coeff 0x49: 0x0249
---
>     Coeff 0x49: 0x0049
360c360
<     Coeff 0x67: 0x3000
---
>     Coeff 0x67: 0xf287

Non-working Case 2 had the same 8 Coeff differences from the Working Case (see above). There were some additional differences between the Working Case and the Non-Working Case 2. The following are the additional differences:

$ diff proc-nonworking-1.txt proc-nonworking-2.txt
77c77
<   Converter: stream=1, channel=0
---
>   Converter: stream=0, channel=0
84c84
<   Power: setting=D0, actual=D0
---
>   Power: setting=D3, actual=D3
202c202
<   Power: setting=D0, actual=D0
---
>   Power: setting=D3, actual=D3

alsa-info output shows that the converter stream and first power setting differences (lines 77,84) are under the heading “Node 0x08 [Audio Input] wcaps 0x10051b: Stereo Amp-In”. The second power setting difference (line 202) is under the heading “Node 0x19 [Pin Complex] wcaps 0x40048b: Stereo Amp-In”

Here are links to the alsa-info output for the three cases (each includes all Coeff values):

Working Case – alsa-info output:
http://www.alsa-project.org/db/?f=86cfcee19a88ab131111d1989038ee1d80fc15b4

Non-working Case 1 – alsa-info output:
http://www.alsa-project.org/db/?f=e3b6bc60eb5086d3b0485b21f8512d30d1e37885

Non-working Case 2 – alsa-info output:
http://www.alsa-project.org/db/?f=f85a7dadac5d1b2d8be5323d930f3e99064e045a

[robertjjoynt]

I managed to fix the problem on my machine. https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1648183

[how_on_earth]

This fix did not work for me. When I created a thread about it here it was deleted; I instead went to the Bugzilla page and I posted a comment there.

[BogdanOlar]

Can confirm that Robert Joynt's solution worked on my HP Omen 15t X7R21AV running Kubuntu 17.04.

That crackling was driving me nuts. I owe you a beer, dude!

[SanityChallngd]

This solution didn't work on my HP Omen 15-ce198wm on Manjaro 18

I did find, however, that after  installing alsa-tools, I could use hdajackretask  to override the  "Black Headphone, left side" Pin ID:0x21 to Internal Speaker.

Select the above, then click on  Install boot override and reboot the machine.

Sound comes out nicely on the headphone jack to my external speakers, and internal speakers still work when the externals are unplugged.

Posting to help others who are looking for a solution after spending 2+ weeks trying to get my external speakers working.

Still looking for a solution to feed sound through the HDMI line to my HP-27WM external monitor.

Both HDMI and external speakers work fine when booting the machine under Windows 10.