Subject: Re: [PATCH 02/14] cxl: Add cxl_slot_is_supported API

From: Frederic Barrat <[email-masked]>
Date: Wed, 6 Jul 2016 18:36:37 +0200

Le 04/07/2016 15:22, Ian Munsie a écrit :
> From: Ian Munsie <[email-masked]>
>
> This extends the check that the adapter is in a CAPI capable slot so
> that it may be called by external users in the kernel API. This will be
> used by the upcoming Mellanox CX4 support, which needs to know ahead of
> time if the card can be switched to cxl mode so that it can leave it in
> PCI mode if it is not.
>
> This API takes a parameter to check if CAPP DMA mode is supported, which
> it currently only allows on P8NVL systems, since that mode currently has
> issues accessing memory < 4GB on P8, and we cannot realistically avoid
> that.
>
> This API does not currently check if a CAPP unit is available (i.e. not
> already assigned to another PHB) on P8. Doing so would be racy since it
> is assigned on a first come first serve basis, and so long as CAPP DMA
> mode is not supported on P8 we don't need this, since the only
> anticipated user of this API requires CAPP DMA mode.

Is it me or that last sentence is more complicated than it should? :-) 
Anyway, I get it.

And the rest looks ok.

Reviewed-by: Frederic Barrat <[email-masked]>