From: joshua stein <jcs@jcs.org>
Subject: Re: nvme: use I/O submission queue entry size reported by controller
To: tech@openbsd.org
Date: Mon, 18 May 2026 20:29:47 -0500

On Tue, 19 May 2026 at 10:35:03 +1000, Jonathan Matthew wrote:
> On Sun, May 17, 2026 at 12:25:57PM -0500, joshua stein wrote:
> > On at least the Apple T2 NVMe, 128-byte submission queue entries on
> > I/O queues are required instead of the standard 64 bytes.
> > 
> > This gets NVMe working on the 2018 Mac Mini.  Also tested on a 
> > non-Apple NVMe but more tests would be helpful.
> 
> I've tested this on a few different nvme devices (real and virtual) and
> haven't seen any problems.
> 
> I'm curious as to why you're using the maximum supported sqe size rather
> than the minimum.  Does the apple T2 nvme not report 128 as the minimum
> size?

No, it reports 64.