For audio, your best solution is ftrace. If you use function_graph option, then you can see the hierarchy of the call sequence. You can also use trace_printk to display variables at specific locations.
BTW, Lauterbach is about $5K investment for the base tool with USB3 connection. You might be able to get something less expensive on eBay, but I doubt if you can get anything less than $1.5. Regards, John > On Apr 6, 2016, at 3:34 PM, Rick Mann <[email protected]> wrote: > > Thanks, John. I've tried printk and other logging, but it's virtually > impossible to trace something like audio, which spans many modules. > > I'll look into Lauterbach. > >> On Apr 6, 2016, at 15:31 , John Syne <[email protected]> wrote: >> >> You can do this with CCSV6 with a USB200 JTAG adapter, but CCSV6 is no >> longer kernel aware. CCSV4 was kernel aware, but won’t work with the current >> kernels. You can still debug with single stepping, software and hardware >> breakpoints, read/write memory, etc. Trying to debug a kernel module without >> a kernel aware debugger is very difficult. Since you don’t know the load >> address of the KM, it is difficult to set a breakpoint on INIT or probe. >> Best to make the driver a kernel builtin so that you can break on the start >> of the driver. >> >> For the most part, most kernel developers use printk to display status at >> strategic locations in their driver. Also, ftrace and dynamic trace tools >> are very useful. Read Documentation/trace on how to use these tools. They >> are very powerful. I have never use KDBG, but that is another solution that >> might work. >> >> I use Lauterbach, which is like the gold standard for Kernel debugging and >> it is kernel aware and has a trace buffer. >> >> Regards, >> John >> >> >> >> >>> On Apr 6, 2016, at 2:56 PM, Rick Mann <[email protected]> wrote: >>> >>> What would I need to get/do to enable me to single-step through kernel code >>> on BBB/G? JTAG header, some kind of interface, and a bunch of software >>> installed on Ubuntu? Can anyone make specific recommendations? Is it even >>> possible? >>> >>> Thanks, >>> >>> -- >>> Rick Mann >>> [email protected] >>> >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google Groups >>> "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. > > > -- > Rick Mann > [email protected] > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
