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From: Christoph Hellwig <hch@infradead.org>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: "Oleksandr Andrushchenko" <andr2000@gmail.com>,
	"Noralf Trønnes" <noralf@tronnes.org>,
	xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org, daniel.vetter@intel.com,
	jgross@suse.com, boris.ostrovsky@oracle.com,
	"Oleksandr Andrushchenko" <oleksandr_andrushchenko@epam.com>
Subject: Re: [PATCH] drm/xen-front: Make shmem backed display buffer coherent
Date: Thu, 20 Dec 2018 07:37:19 -0800	[thread overview]
Message-ID: <20181220153719.GB22997@infradead.org> (raw)
In-Reply-To: <20181219131452.cehks3kabcwuuk7i@sirius.home.kraxel.org>

On Wed, Dec 19, 2018 at 02:14:52PM +0100, Gerd Hoffmann wrote:
> 
> > > > +    if (!dma_map_sg(dev->dev, xen_obj->sgt->sgl, xen_obj->sgt->nents,
> > > > +            DMA_BIDIRECTIONAL)) {
> > > 
> > > 
> > > Are you using the DMA streaming API as a way to flush the caches?
> > Yes
> > > Does this mean that GFP_USER isn't making the buffer coherent?
> > 
> > No, it didn't help. I had a question [1] if there are any other better way
> > to achieve the same, but didn't have any response yet. So, I implemented
> > it via DMA API which helped.
> 
> set_pages_array_*() ?
> 
> See arch/x86/include/asm/set_memory.h

That sounds even more bogus, don't go there.

  parent reply	other threads:[~2018-12-20 15:37 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-27 10:32 [PATCH] drm/xen-front: Make shmem backed display buffer coherent Oleksandr Andrushchenko
2018-12-13 10:17 ` Oleksandr Andrushchenko
2018-12-13 15:48   ` Daniel Vetter
2018-12-14  7:09     ` Oleksandr Andrushchenko
2018-12-14  8:35       ` Daniel Vetter
2018-12-17  8:03         ` Oleksandr Andrushchenko
2018-12-18 19:20 ` Noralf Trønnes
2018-12-19  8:18   ` Oleksandr Andrushchenko
2018-12-19 13:14     ` Gerd Hoffmann
2018-12-19 13:21       ` Oleksandr Andrushchenko
2018-12-19 14:10         ` Gerd Hoffmann
2018-12-20 11:19           ` Oleksandr Andrushchenko
2018-12-20 15:37       ` Christoph Hellwig [this message]
2018-12-19 16:14     ` Noralf Trønnes
2018-12-20 11:24       ` Oleksandr Andrushchenko
2018-12-20 15:36   ` Christoph Hellwig
2018-12-20 15:49     ` Oleksandr Andrushchenko
2018-12-20 17:39       ` Christoph Hellwig
2018-12-20 18:29         ` Daniel Vetter
2018-12-20 18:33           ` Christoph Hellwig
2018-12-20 18:35             ` Daniel Vetter
2018-12-20 18:38               ` Christoph Hellwig
2018-12-21  9:16                 ` Oleksandr Andrushchenko

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