Re: Question about SampleUSBAudioPlugin's functionality.
Re: Question about SampleUSBAudioPlugin's functionality.
- Subject: Re: Question about SampleUSBAudioPlugin's functionality.
- From: email@hidden
- Date: Fri, 28 Jan 2011 13:18:11 -0800
I am looking at the SampleUSBAudioPlugin sample from Apple.
I at the end of the day want to be able to look at the memory where the float samples of audio exist.
I want to be able to hit and view the "mixBuf" float data structure in pluginProcess(),
That piece of code is not being hit, despite playing audio into the USB Audio Device(put some krpintfs and tried logging to /var/log/kernel.log).
Any pointers on what the best way to debug the kext is?
Debugging via /var/log/kernel.log is possible only if that piece of code is being hit.
gdb doesn't seem to be able to break into the driver's methods.
Is there a way to single-step through the kext?
All I see is a bunch of assembly-code when I try to do some debugging via gdb and this is not a lot of information.
Any responses will be appreciated.
~Aruna
Arunasree Swapna
Software Engineer
Logitech
360-817-1360 (office)
Arunasree Swapna---01/27/2011 06:27:39 PM---Hello There, I am trying to break into the Kernel Extension: SampleUSBAudioPlugin's driver methods.
From: Arunasree Swapna/WA/US/LOGITECH
To: email@hidden
Date: 01/27/2011 06:27 PM
Subject: Question about SampleUSBAudioPlugin's functionality.
Hello There,
I am trying to break into the Kernel Extension: SampleUSBAudioPlugin's driver methods.
I tried doing so with gdb, but apparently GDB doesn't give me a facility to do so.
So I tried putting a bunch of debug statement to pipe the messages to /var/log/kernel.log
The sample kext seems to be loading fine from the messages in the /var/log/kernel.log
The kext doe sthe following correctly:
- initializes successfully
- set the direction of frame buffers
- changes the format correctly.
But the rest of the methods don't do anything meaningful, I tried setting the device as default and piping audio into the USB Audio Device set to use this kext.
Who calls the methods in the driver for the driver to do something meaningful?
Any info on that to understand how the sample kernel extension works to do the low-pass filtering stuff?
Thanks in advance.
~Aruna
Arunasree Swapna
Software Engineer
Logitech
360-817-1360 (office)
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