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Date: Wed, 14 Jan 2026 08:21:49 -0700
From: Keith Busch <kbusch@kernel.org>
To: Nilay Shroff <nilay@linux.ibm.com>
Cc: linux-nvme@lists.infradead.org, jmeneghi@redhat.com, wagi@kernel.org,
	axboe@kernel.dk, hch@lst.de, sagi@grimberg.me,
	james.smart@broadcom.com, hare@suse.de, shinichiro.kawasaki@wdc.com,
	wenxiong@linux.ibm.com, nnmlinux@linux.ibm.com, emilne@redhat.com,
	mlombard@redhat.com, gjoyce@ibm.com, stable@vger.kernel.org
Subject: Re: [PATCH] nvme: fix PCIe subsystem reset controller state
 transition
Message-ID: <aWe0ja2rCpRFQEke@kbusch-mbp>
References: <20260114072416.1901394-1-nilay@linux.ibm.com>
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In-Reply-To: <20260114072416.1901394-1-nilay@linux.ibm.com>

On Wed, Jan 14, 2026 at 12:54:13PM +0530, Nilay Shroff wrote:
> The commit d2fe192348f9 ("nvme: only allow entering LIVE from CONNECTING
> state") disallows controller state transitions directly from RESETTING
> to LIVE. However, the NVMe PCIe subsystem reset path relies on this
> transition to recover the controller on PowerPC (PPC) systems.
> 
> On PPC systems, issuing a subsystem reset causes a temporary loss of
> communication with the NVMe adapter. A subsequent PCIe MMIO read then
> triggers EEH recovery, which restores the PCIe link and brings the
> controller back online. For EEH recovery to proceed correctly, the
> controller must transition back to the LIVE state.
> 
> Due to the changes introduced by commit d2fe192348f9 ("nvme: only allow
> entering LIVE from CONNECTING state"), the controller can no longer
> transition directly from RESETTING to LIVE. As a result, EEH recovery
> exits prematurely, leaving the controller stuck in the RESETTING state.
> 
> Fix this by explicitly transitioning the controller state from RESETTING
> to CONNECTING and then to LIVE. This satisfies the updated state
> transition rules and allows the controller to be successfully recovered
> on PPC systems following a PCIe subsystem reset.

Thanks, applied to nvme-6.19.