dri-devel Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Eric Anholt <eric@anholt.net>
To: "Noralf Trønnes" <noralf@tronnes.org>, dri-devel@lists.freedesktop.org
Subject: Re: drm: Why shmem?
Date: Mon, 28 Aug 2017 13:40:41 -0700	[thread overview]
Message-ID: <87wp5n5sty.fsf@anholt.net> (raw)
In-Reply-To: <febc4082-8080-c25f-edf9-343c526d8915@tronnes.org>


[-- Attachment #1.1: Type: text/plain, Size: 778 bytes --]

Noralf Trønnes <noralf@tronnes.org> writes:

> Hi,
>
> Currently I'm using the cma library with tinydrm because it was so
> simple to use even though I have to work around the fact that reads are
> uncached. A bigger problem that I have become aware of, is that it
> restricts the dma buffers it can import since they have to be continous.
>
> So I looked to udl and it uses shmem. Fine, let's make a shmem gem
> library similar to the cma library.
>
> Now I have done so and have started to think about the DOC: section,
> explaining what the library does. And I'm stuck, what's the benefit of
> using shmem compared to just using alloc_page()?

Using shmem means that, when the buffer isn't pinned for DMA usage by
the device, the pages can be swapped out.

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  reply	other threads:[~2017-08-28 20:45 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-28 18:44 drm: Why shmem? Noralf Trønnes
2017-08-28 20:40 ` Eric Anholt [this message]
2017-08-28 20:45 ` Daniel Vetter
2017-08-29 17:40   ` Eric Anholt
2017-08-30  7:40     ` Daniel Vetter
2017-09-14 23:40       ` Noralf Trønnes
2017-09-15  0:45         ` Eric Anholt
2017-09-15 14:38           ` Noralf Trønnes
2017-09-16 22:10             ` Eric Anholt

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=87wp5n5sty.fsf@anholt.net \
    --to=eric@anholt.net \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=noralf@tronnes.org \
    /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