Comment 94 for bug 1066435

Created attachment 347790
emerge --info

ALSA snd-powermac I2C Regression in kernel >3.5.0-rc6+ PPC

ALSA module snd-powermac fails to load on recent kernel versions running on various PPC chips. This makes ALSA unusable for those kernels.

From dmesg:

[ 10.537194] i2c i2c-2: PMac Keywest Audio: attach_adapter method is deprecated
[ 10.537198] i2c i2c-2: Please use another way to instantiate your i2c_client
[ 10.537212] i2c i2c-2: Failed to register i2c client keywest at 0x35 (-16)

Using git-bisect I ascertained where the bug first appeared.

The bug is not present in kernel versions before 3.5.0-rc6+, and all subsequent kernels have the problem.

Here is the commit info from the bisect:

Bisecting: 0 revisions left to test after this (roughly 0 steps)
[3a3dd0186f619b74e61e6f29dddcaf59af7d3cac] i2c/powermac: Improve detection of devices from device-tree
3a3dd0186f619b74e61e6f29dddcaf59af7d3cac is the first bad commit
commit 3a3dd0186f619b74e61e6f29dddcaf59af7d3cac
Author: Benjamin Herrenschmidt <email address hidden>
Date: Mon Jun 18 12:00:50 2012 +1000

    i2c/powermac: Improve detection of devices from device-tree

    This patch adds a number of workarounds for broken Apple device-trees
    mostly around sound chips. It handles creating the missing audio codec
    devices and works around various issues with missing addresses or
    missing compatible properties.

    Signed-off-by: Benjamin Herrenschmidt <email address hidden>

:040000 040000 849b9ecd549338cf00f024c15aaa01d5217e1806 90e49b5143a97c43b4f07040b56dc6002ad51f9b M drivers

I've duplicated this bug on several PPC G4 machines, including:

PowerBook 12 (PowerBook6,1) 12" Aluminum PowerBook G4 867 MHz PowerPC 7455 processor originally released January 7, 2003, model number A1010, order number M8760LL/A

# cat /proc/cpuinfo
processor : 0
cpu : 7455, altivec supported
clock : 867.000000MHz
revision : 3.3 (pvr 8001 0303)
bogomips : 108.20
timebase : 33280414
platform : PowerMac
model : PowerBook6,1
machine : PowerBook6,1
motherboard : PowerBook6,1 MacRISC3 Power Macintosh
detected as : 287 (PowerBook G4 12")
pmac flags : 0000001a
L2 cache : 256K unified
pmac-generation : NewWorld
Memory : 1152 MB

iMac G4 (PowerMac6,1) 17" iMac G4 1.25GHz G4 PowerPC 7457 processor originally released Sep 8, 2003, model number M6498, order number M9168LL/A
# cat /proc/cpuinfo
processor : 0
cpu : 7455, altivec supported
clock : 1249.999995MHz
revision : 3.3 (pvr 8001 0303)
bogomips : 83.20
timebase : 41600571
platform : PowerMac
model : PowerMac6,1
machine : PowerMac6,1
motherboard : PowerMac6,1 MacRISC3 Power Macintosh
detected as : 287 (Flat panel iMac)
pmac flags : 00000010
L2 cache : 256K unified
pmac-generation : NewWorld
Memory : 512 MB

Any help would be much appreciated. Thank You.