Re: [PATCH v2 0/1] nvme: Fix problem when booting from NVMe drive was leading to a hang.

[Christoph Hellwig <hch@lst.de>]

On Mon, Mar 04, 2024 at 10:25:07AM -0800, Michael Kropaczek wrote:
> Description:
> 
> During endurance test, when a system was rebooted from NVMe drive, boot
> process hung occasionally. The number of reboot cycles was set to 1000,
> with interval of 120s. Hang occurred after ~300 reboot cycles.
> After investigating the cause, it was established that NVMe driver
> did not disable host memory during shutdown leaving NVMe controller
> in a state preventing proper initialization in BIOS pre-boot stage.
> Adding of the call to nvme_set_host_mem(dev, 0) when in shutdown
> fixed the issue.

Something odd is going on with your patch submissions, as you seem
to send a single mail with a cover letter and the actual patch.

That's why I missed the last one as I've been waiting for the actual
patch mail which never arrived.

> +	/*
> +	 * On certain host architectures/HW, DRAM was keeping memory contents over reboot-cycles.
> +	 * It was observed that certain controllers were accessing host memory after
> +	 * resetting which led to undefined state preventing proper initialization.
> +	 */

Block comments should never span 80 characters.  But more importantly
I don't even think we need this comment at all, this is a clear bug
fix and the code is self-describing.