[Pkg-alsa-devel] Bug#770122: Bug#770122: patch as workaround/solution

[Elimar Riesebieter]

Control: severity -1 normal
Control: reassign -1 alsa-utils

* Jhonas Wernery <jhony at go4more.de> [2014-11-19 01:20 +0100]:

> I should add the solution:
> 
> I found a workaround on this site
> https://bbs.archlinux.org/viewtopic.php?id=143744
> 
> It basically consists of a patch, installed as a service. I hope the
> maintainers can use this to implement it into the main build so users
> can achieve full sound support on Macbook 5,2 without the need to
> manually add the patch.
> 
> Steps I did to fix the issue of no sound on headphones (following the
> steps explained by helmuthdu in Post #7):



> 1. create a new service 

It is not common, to raise a systemd only solution. 

>                         # nano /etc/systemd/system/alsa-fix.service
> 
> 2. save the script from pezcurrel e.g. like /etc/alsa_fix.py
> 
> #!/usr/bin/env python2
> 
> import os
> import struct
> from fcntl import ioctl
> 
> def __ioctl_val(val):
>   # workaround for OverFlow bug in python 2.4
>   if val & 0x80000000:
>     return -((val^0xffffffff)+1)
>   return val
> 
> IOCTL_INFO = __ioctl_val(0x80dc4801)
> IOCTL_PVERSION = __ioctl_val(0x80044810)
> IOCTL_VERB_WRITE = __ioctl_val(0xc0084811)

What the hell from where did the author got those values? It is
quite unreproducible for me. What doese this script do?

You should doublecheck your mixer settings, don't add any options to
/etc/modprobe.d. Just run a pristine alsa-(base|utils) and libasound2
intstallation.

Please send me a screenshot via PM of

$ xterm -geometry 160x40 -e alsamixer

with and without headphones plugged in.


Is there a $HOME/.asoundrc flowing around?

Elimar
-- 
 Numeric stability is probably not all that
  important when you're guessing;-)