Mark, Lee,

[I wasn't subscribed to alsa-devel when the patch was posted, so I'm sending this as a standalone email instead of as a reply to that]

linux-next 20130924 fails to boot on snowball (u8500_defconfig, non-DT boot):

Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: Oops: 80000005 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-rc1-00003-gff795d6 #135 task: ef060000 ti: ef064000 task.ti: ef064000 PC is at 0x0 LR is at snd_soc_update_bits+0x4c/0x88 pc : [<00000000>] lr : [<c02d4f98>] psr: 60000013 sp : ef065d48 ip : 00000020 fp : ef0d054c r10: 00000000 r9 : ef3c0810 r8 : 00000000 r7 : 00000014 r6 : 00000000 r5 : 00000007 r4 : ef36ea00 r3 : 00000000 r2 : 00000007 r1 : 00000014 r0 : ef36ea00 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c5787d Table: 0000404a DAC: 00000015 Process swapper/0 (pid: 1, stack limit = 0xef064240) Stack: (0xef065d48 to 0xef066000) 5d40: ef153410 c0550bb8 ef153410 ef36ea00 c053dc64 ef36ea00 5d60: c053dc64 c03d5e0c ef36eaac c02e4144 00000000 02000000 ef36ea00 00000000 5d80: c055a688 ef17bc10 ef0a7b00 c02e4358 00000000 00000000 00000000 ef36ea00 5da0: c055a5dc c055a688 c055daa4 c055aa0c ef36eaac c02d74fc c03d592c c055a678 5dc0: ee8115c8 c055daa4 ef0d00c0 00000000 00000000 c055a668 c03d5bf4 c02d8258 5de0: c055dab4 00000000 00000004 eec2d990 c055db7c ef0d0780 c055dbac c055db9c 5e00: c055a6a8 ef36ea30 ef36ea00 ef0d087c ef0d084c ef36ea30 c04a98f4 c055dac4 5e20: c021ce54 c055daa4 000005b8 c053f7f0 c055da64 c051dde8 00000069 ef064028 5e40: 00000000 c02d8ef0 00000000 c055da50 00000000 c02e684c c05924fc c053f7f0 5e60: 00000000 c055da64 c051dde8 c021bc88 c021bc70 c021aa94 00000000 c053f7f0 5e80: c055da64 c053f824 00000000 c021ac80 00000000 c055da64 c021abf4 c0218f6c 5ea0: ef03265c ef1b6734 c055da64 ef192500 c054fea8 c021a220 c0475770 c055da64 5ec0: 00000006 c055da64 00000006 c0563c80 c0563c80 c021b25c 00000000 c052c5f4 5ee0: 00000006 c0008798 ef010900 c04787e4 ef09c100 c03ac5e0 00000000 00000001 5f00: 000014dc c0540b9c 60000013 00000001 00000003 00000000 c0da19bd c03bf6b0 5f20: 00000069 c0036aa4 c04de34c 00000006 c0da19c8 00000006 00000000 c052c5f4 5f40: 00000006 c0563c80 c0563c80 c05014dc 00000069 c0523fec c0523fe0 c0501bc4 5f60: 00000006 00000006 c05014dc 00000000 88000000 00000000 00000000 00000000 5f80: c03a14ec 00000000 00000000 00000000 00000000 00000000 00000000 c03a14f4 5fa0: 00000000 00000000 c03a14ec c000e438 00000000 00000000 00000000 00000000 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 20000000 [<c02d4f98>] (snd_soc_update_bits+0x4c/0x88) from [<c02e4144>] (ab8500_audio_setup_mics+0xc8/0x118) [<c02e4144>] (ab8500_audio_setup_mics+0xc8/0x118) from [<c02e4358>] (ab8500_codec_probe+0x180/0x374) [<c02e4358>] (ab8500_codec_probe+0x180/0x374) from [<c02d74fc>] (soc_probe_codec+0x178/0x2f4) [<c02d74fc>] (soc_probe_codec+0x178/0x2f4) from [<c02d8258>] (snd_soc_instantiate_card+0x794/0x11c0) [<c02d8258>] (snd_soc_instantiate_card+0x794/0x11c0) from [<c02d8ef0>] (snd_soc_register_card+0x26c/0x324) [<c02d8ef0>] (snd_soc_register_card+0x26c/0x324) from [<c02e684c>] (mop500_probe+0xd0/0x118) [<c02e684c>] (mop500_probe+0xd0/0x118) from [<c021bc88>] (platform_drv_probe+0x18/0x1c) [<c021bc88>] (platform_drv_probe+0x18/0x1c) from [<c021aa94>] (driver_probe_device+0x10c/0x228) ...

I bisected it down to:

commit ff795d614bfa62a3c6fc0bcb75cb8842e5a87892 Author: Mark Brown broonie@linaro.org Date: Fri Sep 20 10:38:16 2013 +0100

ASoC: ab8500: Convert register I/O to regmap

As part of a general push to eliminate the duplicated register I/O support in ASoC convert ab8500 to use regmap.

Signed-off-by: Mark Brown broonie@linaro.org Acked-by: Lee Jones lee.jones@linaro.org

... but I didn't look closer at what was actually broken.

-Olof