[SOLVED] Where to find function definition in Linux kernel?

Malvineous · 2012-05-07 01:42:42

Hi all,

I'm looking at the Linux kernel source, and in sound/pci/hda/hda_codec.c around line 4119 there is a call to a function called "trace_hda_power_down". I can't find where this function is defined though. Does anyone know? I've tried grepping the entire source tree but this function isn't mentioned anywhere else. I am able to compile the code without errors, so it must be defined somewhere, but I can't see where!

Last edited by Malvineous (2012-05-07 03:48:02)

drcouzelis · 2012-05-07 02:41:25

Wow, I agree, that's a tricky one!

I noticed it's surrounded by a "CONFIG_SND_HDA_POWER_SAVE" conditional. Do you have "CONFIG_SND_HDA_POWER_SAVE" set to "Y" in your kernel configuration?

Malvineous · 2012-05-07 02:46:25

Yes, it's definitely defined. (The problem I am investigating is related to power saving happening when it shouldn't.) There are a bunch of other trace_* functions too which also don't seem to be defined, but I can't find any documentation about what they're for or why they seem to compile when they apparently haven't been declared! They must be declared within a macro somewhere...

falconindy · 2012-05-07 03:29:14

Any function prefixed with 'trace' is generated code as part of the trace subsystem. You won't find an exact definition for it, because it's just a macro: see the hda_codec.h include in the same directory.

Malvineous · 2012-05-07 03:47:46

Ah right, it looks like they're defined in hda_trace.h. Now to hunt for docs on the trace subsystem... Thanks both for your help!

Arch Linux

#1 2012-05-07 01:42:42

[SOLVED] Where to find function definition in Linux kernel?

#2 2012-05-07 02:41:25

Re: [SOLVED] Where to find function definition in Linux kernel?

#3 2012-05-07 02:46:25

Re: [SOLVED] Where to find function definition in Linux kernel?

#4 2012-05-07 03:29:14

Re: [SOLVED] Where to find function definition in Linux kernel?

#5 2012-05-07 03:47:46

Re: [SOLVED] Where to find function definition in Linux kernel?

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