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From: "hch@lst.de" <hch@lst.de>
To: "Koenig, Christian" <Christian.Koenig@amd.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>,
	"hch@lst.de" <hch@lst.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"yong.zhi@intel.com" <yong.zhi@intel.com>,
	"daniel.vetter@ffwll.ch" <daniel.vetter@ffwll.ch>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
	"bingbu.cao@intel.com" <bingbu.cao@intel.com>,
	"jian.xu.zheng@intel.com" <jian.xu.zheng@intel.com>,
	"tian.shu.qiu@intel.com" <tian.shu.qiu@intel.com>,
	"shiraz.saleem@intel.com" <shiraz.saleem@intel.com>,
	"sakari.ailus@linux.intel.com" <sakari.ailus@linux.intel.com>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>, "jgg@ziepe.ca" <jgg@ziepe.ca>
Subject: Re: [PATCH] lib/scatterlist: Provide a DMA page iterator
Date: Wed, 16 Jan 2019 17:06:39 +0100	[thread overview]
Message-ID: <20190116160639.GA28619@lst.de> (raw)
In-Reply-To: <8aadac80-da9b-b52a-a4bf-066406127117@amd.com>

On Wed, Jan 16, 2019 at 07:28:13AM +0000, Koenig, Christian wrote:
> To summarize once more: We have an array of struct pages and want to 
> coherently map that to a device.

And the answer to that is very simple: you can't.  What is so hard
to understand about?  If you want to map arbitrary memory it simply
can't be done in a coherent way on about half of our platforms.

> If that is not possible because of whatever reason we want to get an 
> error code or even not load the driver from the beginning.

That is a bullshit attitude.  Just like everyone else makes their
drivers work you should not be lazy.

> > bool dma_streaming_is_coherent(const struct device *)
> >
> > API to help us decide when to load or not.
> 
> Yes, please.

Hell no.

  parent reply	other threads:[~2019-01-16 16:06 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-04 22:35 [PATCH] lib/scatterlist: Provide a DMA page iterator Jason Gunthorpe
2019-01-05  2:37 ` kbuild test robot
2019-01-05  3:21   ` Jason Gunthorpe
2019-01-10 23:42 ` Jason Gunthorpe
2019-01-14  9:48   ` Christoph Hellwig
2019-01-15 14:17     ` Thomas Hellstrom
2019-01-15 14:24       ` Christian König
2019-01-15 15:20         ` hch
2019-01-15 18:03           ` Thomas Hellstrom
2019-01-15 18:31             ` hch
2019-01-15 19:13               ` Koenig, Christian
2019-01-15 20:58                 ` hch
2019-01-16  7:09                   ` Thomas Hellstrom
2019-01-16  7:28                     ` Koenig, Christian
2019-01-16 10:14                       ` Daniel Vetter
2019-01-16 16:06                       ` hch [this message]
2019-01-16 16:36                         ` Daniel Stone
2019-01-15 21:25       ` Jason Gunthorpe
2019-01-16 10:40         ` Christian König
2019-01-16 16:11         ` hch
2019-01-16 17:24           ` Jason Gunthorpe
2019-01-17  9:30             ` hch
2019-01-17 10:47               ` Thomas Hellstrom
2019-01-17 15:54               ` Jason Gunthorpe
2019-01-12 18:27 ` Shiraz Saleem
2019-01-12 18:37   ` Jason Gunthorpe
2019-01-12 19:03     ` Shiraz Saleem
2019-01-14  9:46       ` Christoph Hellwig
2019-01-14 22:16       ` Jason Gunthorpe
2019-02-07 23:23 ` Sakari Ailus

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