Intel-GFX Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: John.C.Harrison@Intel.com
To: Intel-GFX@Lists.FreeDesktop.Org
Cc: DRI-Devel@Lists.FreeDesktop.Org
Subject: [Intel-gfx] [PATCH v2 0/2] Don't use stolen memory or BAR mappings for ring buffers
Date: Wed, 15 Feb 2023 16:22:46 -0800	[thread overview]
Message-ID: <20230216002248.1851966-1-John.C.Harrison@Intel.com> (raw)

From: John Harrison <John.C.Harrison@Intel.com>

Instruction from hardware arch is that stolen memory and BAR mappings
are unsafe for use as ring buffers. There can be issues with cache
aliasing due to the CPU access going to memory via the BAR. So, don't
do it.

v2: Dont use BAR mappings either.
Make conditional on LLC so as not to change platforms that don't need
to change (Daniele).
Add 'Fixes' tags (Tvrtko).

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>


Daniele Ceraolo Spurio (1):
  drm/i915: Don't use BAR mappings for ring buffers with LLC

John Harrison (1):
  drm/i915: Don't use stolen memory for ring buffers with LLC

 drivers/gpu/drm/i915/gt/intel_ring.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

-- 
2.39.1


             reply	other threads:[~2023-02-16  0:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-16  0:22 John.C.Harrison [this message]
2023-02-16  0:22 ` [Intel-gfx] [PATCH v2 1/2] drm/i915: Don't use stolen memory for ring buffers with LLC John.C.Harrison
2023-02-16  0:22 ` [Intel-gfx] [PATCH v2 2/2] drm/i915: Don't use BAR mappings " John.C.Harrison
2023-02-16  2:54   ` kernel test robot
2023-02-16  8:47   ` kernel test robot
2023-02-16  0:58 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for Don't use stolen memory or BAR mappings for ring buffers Patchwork

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=20230216002248.1851966-1-John.C.Harrison@Intel.com \
    --to=john.c.harrison@intel.com \
    --cc=DRI-Devel@Lists.FreeDesktop.Org \
    --cc=Intel-GFX@Lists.FreeDesktop.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