解决linux下Realtek ALC295的耳机炸裂声

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个人使用的笔记本是暗影精灵2 PRO,产品名称是: OMEN by HP Laptop 15-ax210TX.

最初本人装的是ubuntu,左边耳机的声音一直有噼里啪啦的炸裂声,后来换了Arch还是一样的情况,而且本人喜欢听安静的声音,类似读故事或是心跳声这种,每次听到劈裂啪啦的声音真是难受.

最初尝试过Arch wiki中的各种方法 包括

PulseAudio/Troubleshooting#Glitches,_skips_or_crackling
PulseAudio/Troubleshooting#Static_noise_when_using_headphones

都没有任何改进.

直到后来才发现这是linux下Realtek ALC295的驱动不完善导致的,这个bug在17年就提出了,至今都没有得到解决.

Bug 195457 - Realtek ALC295 still unsupported
Crackling and popping sound when using headphones

即使有人提交补丁并合并到了linux内核中

ALSA: hda - Fix missing COEF init for ALC225/295/299

但是事实证明并没有用

依照上面有人提供的方法却有效(看起来跟提交补丁差不多,但是补丁却没有起作用):

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I've managed to fix this problem on my machine (HP Omen 15 running Ubuntu 17.04 using codec for Realtek ALC295 sound device). To fix the problem, I can do the following:

Install alsa-tools if not installed:

sudo apt install alsa-tools

Create and save a script in /usr/local/bin:

#!/bin/bash
hda-verb /dev/snd/hwC0D0 0x20 SET_COEF_INDEX 0x67
hda-verb /dev/snd/hwC0D0 0x20 SET_PROC_COEF 0x3000

Run the script as root in a terminal to immediately fix the problem.

To run the script on startup, use cron with the @reboot command:

sudo crontab -e

and then add line in crontab:
@reboot [full path to script]

To run script on resume from suspend, copy the script to /lib/systemd/system-sleep

For more technical details regarding this fix, see https://bugzilla.kernel.org/show_bug.cgi?id=195457

arch下类似 除了是用pacman安装alsa-tools,之后操作是一样的.

不使用crontab,使用systemd的方法ASUS_Zenbook_UX430/UX530#Headphones_audio_is_too_low

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In order to fix it, install alsa-tools or hda-verbAUR and create the file:

/usr/local/bin/fix_headphones_audio.sh
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#!/bin/bash
while true; do
    DEVICE=`ls /dev/snd/hwC[[:print:]]*D0 | head -n 1`
    if [ ! -z "$DEVICE" ]; then
        hda-verb "$DEVICE" 0x20 SET_COEF_INDEX 0x67
        hda-verb "$DEVICE" 0x20 SET_PROC_COEF 0x3000
        break
    fi
    sleep 1
done
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Then create a systemd script with the following content:

/etc/systemd/system/fix_headphones_audio.service
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[Unit]
Description=Fix headphones audio after boot & resume.
After=multi-user.target suspend.target hibernate.target

[Service]
Type=oneshot
ExecStart=/bin/sh '/usr/local/bin/fix_headphones_audio.sh'

[Install]
WantedBy=multi-user.target suspend.target hibernate.target
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And finally, start and enable fix_headphones_audio.service.

Bug 195457 - Realtek ALC295 still unsupported
Crackling and popping sound when using headphones
How to install Bang and Olufsen Audio drivers for HP laptop?
ASUS_Zenbook_UX430/UX530#Headphones_audio_is_too_low