From: James Hogan <jhogan@kernel.org>
To: Matt Redfearn <matt.redfearn@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>,
linux-mips@linux-mips.org, Paul Burton <paul.burton@mips.com>,
Dengcheng Zhu <dengcheng.zhu@mips.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v3] MIPS: pm-cps: Block system suspend when a JTAG probe is present
Date: Fri, 9 Mar 2018 13:55:49 +0000 [thread overview]
Message-ID: <20180309135548.GF24558@saruman> (raw)
In-Reply-To: <1519120696-30658-1-git-send-email-matt.redfearn@mips.com>
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On Tue, Feb 20, 2018 at 09:58:16AM +0000, Matt Redfearn wrote:
> If a JTAG probe is connected to a MIPS cluster, then the CPC detects it
> and latches the CPC.STAT_CONF.EJTAG_PROBE bit to 1. While set,
> attempting to send a power-down command to a core will be blocked, and
> the CPC will instead send the core to clock-off state. This can
> interfere with systems fully entering a low power state where all
> cores, CM, GIC, etc are powered down.
>
> Detect that a JTAG probe is / has been connected to the cluster and
> block the suspend attempt.
>
> Attempting to suspend the system while a JTAG probe is connected now
> yields:
> # echo mem > /sys/power/state
> [ 11.654000] PM: Syncing filesystems ... done.
> [ 11.658000] JTAG probe is connected - abort suspend
> -sh: echo: write error: Operation not permitted
> #
>
> To restore suspend, the JTAG probe should be disconnected or put into
> quiescent state. Platform code can then clear the
> CPC.STAT_CONF.EJTAG_PROBE bit.
>
> Reported-by: Ed Blake <ed.blake@sondrel.com>
> Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Thanks, applied for 4.17.
Cheers
James
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prev parent reply other threads:[~2018-03-09 13:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-20 9:58 [PATCH v3] MIPS: pm-cps: Block system suspend when a JTAG probe is present Matt Redfearn
2018-03-09 13:55 ` James Hogan [this message]
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