From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Thomas Hellstrom <thellstrom@vmware.com>
Cc: "intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH] drm/mm: Support 4 GiB and larger ranges
Date: Tue, 27 Jan 2015 21:26:27 +0000 [thread overview]
Message-ID: <20150127212627.GO26493@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <54C74CDE.2010409@vmware.com>
On Tue, Jan 27, 2015 at 09:31:26AM +0100, Thomas Hellstrom wrote:
> On 01/27/2015 09:15 AM, Thierry Reding wrote:
> > Are you referring to the 4 GiB - 1 comment? The point I was trying to
> > make is not that the granularity of the IOVA space needs to be 1 byte
> > but rather that using an unsigned long for a size on a 32-bit machine
> > will give you 4 GiB - 1 addresses. The IOMMU page size is still 4 KiB
> > for Tegra.
>
> I was rather referring to that if the range manager (drm_mm) is set up
> to manage pages instead of bytes
> (like, for example, the TTM VM address space), you'd get 4G - 1 pages,
> which, I believe, is sufficient on most 32 bit systems?
It'd probably also be more efficient on 32-bit systems rather than
shifting them over to using 64-bit quantities.
If the allocation granularity were to move to pages, would it be worth
moving to a pfn-based addressing system too, rather than sticking with
a byte address there too?
--
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2015-01-27 21:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-23 8:05 [PATCH] drm/mm: Support 4 GiB and larger ranges Thierry Reding
2015-01-26 22:51 ` Dave Airlie
2015-01-27 6:07 ` Thomas Hellstrom
2015-01-27 8:15 ` Thierry Reding
2015-01-27 8:31 ` Thomas Hellstrom
2015-01-27 21:26 ` Russell King - ARM Linux [this message]
2015-01-27 9:22 ` Chris Wilson
2015-01-26 23:09 ` Alex Deucher
2015-03-04 16:20 ` Alex Deucher
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=20150127212627.GO26493@n2100.arm.linux.org.uk \
--to=linux@arm.linux.org.uk \
--cc=daniel.vetter@intel.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=thellstrom@vmware.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.