From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: convert 'iommu_alloc failed' messages to dynamic debug
Date: Tue, 14 Jun 2016 07:26:56 +1000 [thread overview]
Message-ID: <1465853216.3022.26.camel@kernel.crashing.org> (raw)
In-Reply-To: <575EB4DE.9080807@linux.vnet.ibm.com>
On Mon, 2016-06-13 at 10:27 -0300, Mauricio Faria de Oliveira wrote:
> Hi Ben,
>
> On 06/11/2016 08:02 PM, Benjamin Herrenschmidt wrote:
> > I'm not fan of this. This is a very useful message to diagnose why,
> > for example, your network adapter is not working properly.
> >
> > A lot of drivers don't deal well with IOMMU errors.
> >
> > The fact that NVME trigger these is a problem that needs to be
> > solved
> > differently.
>
> Ok, I understand your points.
>
> Thanks for the review -- helps in setting another direction.
I've been thinking about this a bit... it might be worthwhile adding
a dma_* call to query the approximate size of the IOMMU window, as
a way for the device to adjust its requirements dynamically.
Another option would be to use a dma_attr for silencing mapping errors
which NVME could use provided it does handle them gracefully ...
Cheers,
Ben.
next prev parent reply other threads:[~2016-06-13 21:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-10 13:03 [PATCH] powerpc: convert 'iommu_alloc failed' messages to dynamic debug Mauricio Faria de Oliveira
2016-06-11 23:02 ` Benjamin Herrenschmidt
2016-06-13 13:27 ` Mauricio Faria de Oliveira
2016-06-13 21:26 ` Benjamin Herrenschmidt [this message]
2016-06-13 21:43 ` Mauricio Faria de Oliveira
2016-06-13 21:51 ` Benjamin Herrenschmidt
2016-06-13 22:01 ` Mauricio Faria de Oliveira
2016-08-03 19:39 ` Mauricio Faria de Oliveira
2016-08-03 21:34 ` Benjamin Herrenschmidt
2016-08-03 21:39 ` Mauricio Faria de Oliveira
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