From: "Christian König" <christian.koenig@amd.com>
To: Taimuraz Kaitmazov <taimuraz@kaitmazov.com>,
Lizhi Hou <lizhi.hou@amd.com>
Cc: Min Ma <mamin506@gmail.com>, Oded Gabbay <ogabbay@kernel.org>,
Sumit Semwal <sumit.semwal@linaro.org>,
Max Zhen <max.zhen@amd.com>, Sonal Santan <sonal.santan@amd.com>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org
Subject: Re: [PATCH v2 0/5] accel/amdxdna: honour the SYNC_BO range
Date: Fri, 14 Aug 2026 09:59:22 +0200 [thread overview]
Message-ID: <0cde1787-fe35-4832-9a28-6313e006fe38@amd.com> (raw)
In-Reply-To: <20260813182905.124248-1-taimuraz@kaitmazov.com>
On 8/13/26 20:29, Taimuraz Kaitmazov wrote:
> On 8/13/26 09:44, Christian König wrote:
>> An alternative would be to use DMA_BUF_IOCTL_SYNC from userspace
>
> Tried it against amdgpu, imported into amdxdna: stale on all 20 runs, no
> better than no sync at all. SYNC_BO on the same buffer is clean on all
> 20.
That is expected, as I said this is for the case when a device which can't snoop the CPU cache exports a buffer.
> Which leaves me no legal way to import a buffer the CPU also reads. Is
> there one I'm missing, or should a device like this just not import?
Yes, exactly that.
For the case where a device which can't snoop imports a buffer we simply don't have an interface at all.
In other words amdxdna can export a buffer which others drivers import, but if the xdna HW is not capable of snooping the CPU cache it is not possible for the driver to provide an import functionality.
Regards,
Christian.
prev parent reply other threads:[~2026-08-14 7:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260811231351.1011244-1-taimuraz@kaitmazov.com>
2026-08-12 8:57 ` [PATCH v2 0/5] accel/amdxdna: honour the SYNC_BO range Christian König
2026-08-12 15:45 ` Lizhi Hou
2026-08-13 7:44 ` Christian König
2026-08-13 18:08 ` Lizhi Hou
2026-08-13 18:54 ` Alex Deucher
[not found] ` <20260813195059.149991-1-taimuraz@kaitmazov.com>
2026-08-13 20:06 ` Alex Deucher
[not found] ` <20260813201416.158728-1-taimuraz@kaitmazov.com>
2026-08-13 21:02 ` Lizhi Hou
[not found] ` <20260813182905.124248-1-taimuraz@kaitmazov.com>
2026-08-13 19:01 ` Lizhi Hou
2026-08-14 7:59 ` Christian König [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=0cde1787-fe35-4832-9a28-6313e006fe38@amd.com \
--to=christian.koenig@amd.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=lizhi.hou@amd.com \
--cc=mamin506@gmail.com \
--cc=max.zhen@amd.com \
--cc=ogabbay@kernel.org \
--cc=sonal.santan@amd.com \
--cc=sumit.semwal@linaro.org \
--cc=taimuraz@kaitmazov.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