Re: ftrace doesn't work - 1211 upstream kernel

[Mark Zhang <nvmarkzhang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Terje, did yo test the ToT(1211) kernel?

Could you tell me which ftrace configs you enabled?
And what is your kernel command line?

Mark
On 12/12/2012 08:26 PM, Terje Bergström wrote:
> On 12.12.2012 13:27, Mark Zhang wrote:
>> Hi all,
>>
>> Has anyone tried to use ftrace to debug upstream kernel? I tried today
>> but the result is, the serial console hung after ftrace enabled(kernel
>> is alive because the Magic SysRq works).
>>
>> My steps are:
>> - Enable CONFIG_FUNCTION_TRACER in kernel config
>> - Enter command: echo 0 > /sys/kernel/debug/tracing/tracing_on;echo
>> function > /sys/kernel/debug/tracing/current_tracer;echo 1 >
>> /proc/sys/kernel/ftrace_dump_on_oops
>> - Then sometimes the serial console hangs right after you entered the
>> command above, or hangs when you try to "cat /sys/kernel/debug/trace"
>>
>> I dumped some backtraces(check below, by invoking a system crash
>> manually) and hope it helps:
> 
> I'm using ftrace to debug host1x driver + tegradrm, running on Tegra2
> ventana. I just rebased them on linux-next, and I use just the events,
> not function tracing.
> 
> echo 1 >/sys/kernel/debug/tracing/events/host1x/enable
> ~/drm/tests/tegra/2d/tegra_2d_tests
> cat /sys/kernel/debug/tracing/trace
> 
> I get host1x events as expected.
> 
> Also function tracing works.
> 
> Terje
>