From: "hch@lst.de" <hch@lst.de>
To: "Hellstrom, Thomas" <thomas.hellstrom@intel.com>
Cc: "daniel@ffwll.ch" <daniel@ffwll.ch>,
"joonas.lahtinen@linux.intel.com"
<joonas.lahtinen@linux.intel.com>,
"Vivi, Rodrigo" <rodrigo.vivi@intel.com>,
"bob.beckett@collabora.com" <bob.beckett@collabora.com>,
"tvrtko.ursulin@linux.intel.com" <tvrtko.ursulin@linux.intel.com>,
"jani.nikula@linux.intel.com" <jani.nikula@linux.intel.com>,
"airlied@linux.ie" <airlied@linux.ie>, "hch@lst.de" <hch@lst.de>,
"Ursulin, Tvrtko" <tvrtko.ursulin@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"kernel@collabora.com" <kernel@collabora.com>,
"Auld, Matthew" <matthew.auld@intel.com>,
"intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH v5] drm/i915: stop using swiotlb
Date: Tue, 9 Aug 2022 20:51:57 +0200 [thread overview]
Message-ID: <20220809185157.GA15307@lst.de> (raw)
In-Reply-To: <1160a7c31084ab2259088e4bfe88b41ad61c2bcc.camel@intel.com>
On Mon, Aug 08, 2022 at 03:48:02PM +0000, Hellstrom, Thomas wrote:
> This whole thing looks a bit strange to me since with SWIOTLB actually
> used for i915, the driver should malfunction anyway as it doesn't do
> any dma_sync_sg_for_cpu() or dma_sync_sg_for_device(),
Yeah, I can't actually see any syncs in i915.
> and the driver
> assumes all coherent dma. Is that SWIOTLB=force kernel option still
> available?
Yes, although it is (and always has been) lower case swiotlb for the
option.
> Also, correct me if I'm wrong, but the original driver segment size
> appears to mean "the largest contiguous area that can be handled either
> by the device or the dma mapping layer" rather than the total space
> available for dma mappings? Not completely sure what
> dma_max_mapping_size() is returning, though?
dma_max_mapping_size is sort of both. It is is the largest contigous
size, but we really should not go above that to avoid starvation.
prev parent reply other threads:[~2022-08-09 19:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-26 15:39 [PATCH v5] drm/i915: stop using swiotlb Robert Beckett
2022-08-08 15:48 ` Hellstrom, Thomas
2022-08-09 11:36 ` Tvrtko Ursulin
2022-08-09 18:54 ` hch
2022-08-09 18:51 ` hch [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220809185157.GA15307@lst.de \
--to=hch@lst.de \
--cc=airlied@linux.ie \
--cc=bob.beckett@collabora.com \
--cc=daniel@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=jani.nikula@linux.intel.com \
--cc=joonas.lahtinen@linux.intel.com \
--cc=kernel@collabora.com \
--cc=linux-kernel@vger.kernel.org \
--cc=matthew.auld@intel.com \
--cc=rodrigo.vivi@intel.com \
--cc=thomas.hellstrom@intel.com \
--cc=tvrtko.ursulin@intel.com \
--cc=tvrtko.ursulin@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox