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From:   Balbir Singh <bsingharora@gmail.com>
Date:   Mon, 12 Feb 2018 22:12:13 +1100
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Subject: Re: [PATCH] powerpc/xmon: Dont register sysrq key when kernel param xmon=off
To:     Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Cc:     "open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)" 
        <linuxppc-dev@lists.ozlabs.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Douglas Miller <dougmill@linux.vnet.ibm.com>,
        Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
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On Mon, Feb 12, 2018 at 7:59 PM, Vaibhav Jain
<vaibhav@linux.vnet.ibm.com> wrote:
> Presently sysrq key for xmon('x') is registered during kernel init
> irrespective of the value of kernel param 'xmon'. Thus xmon is enabled
> even if 'xmon=off' is passed on the kernel command line.
>
> This minor patch updates setup_xmon_sysrq() to register
> 'sysrq_xmon_op' only when variable 'xmon_on' is set.
>
> Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
> ---

Any specific issue you've run into without this patch? I presume
running xmon=off indicates we don't want xmon to take over in case of
panic/die/oops, why are we tying this to sysrq?

Balbir Singh.