Re: [Linuxptp-devel] Issues with mutex locking and ptp_find_pin

[Richard C. <ric...@gm...>]

On Thu, Jan 14, 2016 at 01:57:02PM -0800, Andrew Symington wrote:
> I just modified the Linux TI CPTS driver to support external hardware time
> stamping. In my driver's .enable function callback on the *ptp_clock_info*
> struct I made use of the *ptp_find_pin* to map a (function,channel) to a
> (pin). Using the testptp.c app I am able to successfully switch to func=1
> (EXTTS) mode and time stamping works. However, when I try and switch back
> to func=0 (NONE) the testptp application hangs, and I get a kernel panic
> (slow mutex).

It is hard to figure out what went wrong without seeing the code.
Please show us your diff.

> Perhaps it isn't a good practice to call *ptp_find_pin *from within the
> enable function callback in driver code, as done in
> /drivers/net/ethernet/intel/igb/igb_ptp.c.

I think igb is working just fine:

	# testptp -l
	name SDP0 index 0 func 0 chan 0
	name SDP1 index 1 func 0 chan 0
	name SDP2 index 2 func 0 chan 0
	name SDP3 index 3 func 0 chan 0

	# testptp -L 0,1
	set pin function okay

	# testptp -l
	name SDP0 index 0 func 1 chan 0
	name SDP1 index 1 func 0 chan 0
	name SDP2 index 2 func 0 chan 0
	name SDP3 index 3 func 0 chan 0

	# testptp -L 0,0
	set pin function okay

	# testptp -l
	name SDP0 index 0 func 0 chan 0
	name SDP1 index 1 func 0 chan 0
	name SDP2 index 2 func 0 chan 0
	name SDP3 index 3 func 0 chan 0

Thanks,
Richard