From: Gerd Hoffmann <kraxel@redhat.com>
To: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>
Cc: Guillaume.Gardet@arm.com, David Airlie <airlied@linux.ie>,
open list <linux-kernel@vger.kernel.org>,
stable@vger.kernel.org, gurchetansingh@chromium.org,
dri-devel@lists.freedesktop.org, tzimmermann@suse.de
Subject: Re: [PATCH v5 1/3] drm/shmem: add support for per object caching flags.
Date: Thu, 27 Feb 2020 11:56:43 +0100 [thread overview]
Message-ID: <20200227105643.h4klc3ybhpwv2l3x@sirius.home.kraxel.org> (raw)
In-Reply-To: <41ca197c-136a-75d8-b269-801db44d4cba@shipmail.org>
Hi,
> I think it might be safe for some integrated graphics where the driver
> maintainers can guarantee that it's safe on all particular processors used
> with that driver, but then IMO it should be moved out to those drivers.
>
> Other drivers needing write-combine shouldn't really use shmem.
>
> So again, to fix the regression, could we revert 0be895893607f ("drm/shmem:
> switch shmem helper to &drm_gem_object_funcs.mmap") or does that have other
> implications?
This patch isn't a regression. The old code path has the
pgprot_writecombine() call in drm_gem_mmap_obj(), so the behavior
is the same before and afterwards.
But with the patch in place we can easily have shmem helpers do their
own thing instead of depending on whatever drm_gem_mmap_obj() is doing.
Just using cached mappings unconditionally would be perfectly fine for
virtio-gpu.
Not sure about the other users though. I'd like to fix the virtio-gpu
regression (coming from ttm -> shmem switch) asap, and I don't feel like
changing the behavior for other drivers in 5.6-rc is a good idea.
So I'd like to push patches 1+2 to -fixes and sort everything else later
in -next. OK?
cheers,
Gerd
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-02-27 10:56 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 15:47 [PATCH v5 0/3] drm/virtio: fix mmap page attributes Gerd Hoffmann
2020-02-26 15:47 ` [PATCH v5 1/3] drm/shmem: add support for per object caching flags Gerd Hoffmann
2020-02-26 16:51 ` Guillaume Gardet
2020-02-26 18:24 ` Thomas Hellström (VMware)
2020-02-27 0:02 ` Chia-I Wu
2020-02-27 7:16 ` Thomas Hellström (VMware)
2020-02-27 7:53 ` Gerd Hoffmann
2020-02-27 8:10 ` Thomas Hellström (VMware)
2020-02-27 10:56 ` Gerd Hoffmann [this message]
2020-02-27 12:16 ` Thomas Hellström (VMware)
2020-02-27 13:21 ` Gerd Hoffmann
2020-02-27 13:44 ` Thomas Hellström (VMware)
2020-02-27 13:49 ` Thomas Hellström (VMware)
2020-02-28 9:49 ` Gerd Hoffmann
2020-02-28 9:54 ` Thomas Hellström (VMware)
2020-02-28 10:46 ` Gerd Hoffmann
2020-03-02 1:56 ` Qiang Yu
2020-02-26 15:47 ` [PATCH v5 2/3] drm/virtio: fix mmap page attributes Gerd Hoffmann
2020-02-26 16:52 ` Guillaume Gardet
2020-02-26 15:47 ` [PATCH v5 3/3] drm/udl: simplify gem object mapping Gerd Hoffmann
2020-02-26 17:03 ` [PATCH v5 0/3] drm/virtio: fix mmap page attributes Gurchetan Singh
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=20200227105643.h4klc3ybhpwv2l3x@sirius.home.kraxel.org \
--to=kraxel@redhat.com \
--cc=Guillaume.Gardet@arm.com \
--cc=airlied@linux.ie \
--cc=dri-devel@lists.freedesktop.org \
--cc=gurchetansingh@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=thomas_os@shipmail.org \
--cc=tzimmermann@suse.de \
/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;
as well as URLs for NNTP newsgroup(s).