Re: [PATCH] powerpc/xmon: add debugfs entry for xmon

Pan Xinhui [off-list ref] writes:

=E5=9C=A8 2017/2/14 10:35, Nicholas Piggin =E5=86=99=E9=81=93:

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On Mon, 13 Feb 2017 19:00:42 -0200
"Guilherme G. Piccoli" [off-list ref] wrote:

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* I had this patch partially done for some time, and after a discussion
at the kernel slack channel latest week, I decided to rebase and fix
some remaining bugs. I'd change 'x' option to always disable the debugg=

er,

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since with this patch we can always re-enable xmon, but today I noticed
Pan's patch on the mailing list, so perhaps his approach of adding a fl=

ag

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to 'x' option is preferable. I can change this in a V2, if requested.
Thanks in advance!

xmon state changing after the first sysrq+x violates principle of least
astonishment, so I think that should be fixed.

Hi, Guilherme
So in the end, my thought is that:
1) cmd x|X will exit xmon and keep xmon in the original state

Agreed.

2) Then add options to turn some features on/off. And debugfs maybe
not fit for this. But I am also wondering at same time, are people
needing this?

I think it's useful. Especially seeing as Guilherme has already written
the code.

And yeah I think debugfs is the right place to do it. It means you can
query and/or set the xmon state without crashing the box - which is what
entering xmon essentially does, even if you later recover.

cheers