Re: [PATCH v3] nvme-pci: Support shared tags across queues for Apple 2018 controllers
From: Balbir Singh
Date: Fri Jul 19 2019 - 01:45:41 EST
On Fri, Jul 19, 2019 at 3:31 PM Benjamin Herrenschmidt
> From 8dcba2ef5b1466b023b88b4eca463b30de78d9eb Mon Sep 17 00:00:00 2001
> From: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Date: Fri, 19 Jul 2019 15:03:06 +1000
> Another issue with the Apple T2 based 2018 controllers seem to be
> that they blow up (and shut the machine down) if there's a tag
> collision between the IO queue and the Admin queue.
> My suspicion is that they use our tags for their internal tracking
> and don't mix them with the queue id. They also seem to not like
> when tags go beyond the IO queue depth, ie 128 tags.
> This adds a quirk that marks tags 0..31 of the IO queue reserved
> Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Balbir Singh <bsingharora@xxxxxxxxx>