From: "Michel Dänzer" <michel@daenzer.net>
To: Rui Salvaterra <rsalvaterra@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: "Christian König" <ckoenig.leichtzumerken@gmail.com>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
"debian-powerpc@lists.debian.org"
<debian-powerpc@lists.debian.org>,
"John Paul Adrian Glaubitz" <glaubitz@physik.fu-berlin.de>,
"Karoly Balogh (Charlie/SGR)" <charlie@scenergy.dfmk.hu>
Subject: Re: [RFC] Remove AGP support from Radeon/Nouveau/TTM
Date: Wed, 13 May 2020 12:26:53 +0200 [thread overview]
Message-ID: <69696543-7c0e-604d-ed29-721b1b99d44e@daenzer.net> (raw)
In-Reply-To: <CALjTZvZNb-KbdZwM3kLU4yK8zH+NSh35k=iBtfGJMF1xyjpSFg@mail.gmail.com>
On 2020-05-13 11:28 a.m., Rui Salvaterra wrote:
> On Wed, 13 May 2020 at 08:19, Daniel Vetter <daniel@ffwll.ch> wrote:
>>
>> i915 is even worse, we manually mess around with clflush. In
>> userspace. So really there's 2 axis for dma memory: coherent vs.
>> non-coherent (which is something the dma-api somewhat exposed), i.e.
>> do you need to clflush or not, and cached vs uncached, i.e. are the
>> PAT entries wc or wb.
>
> So, the PowerPC AGP GART ends up being cached and non-coherent, right
> (assuming there's no way to set the page attributes MTRR/PAT-style)?
It was uncached when I was using my last-gen PowerBook (until a few
years ago), though it's possible that broke since then. I don't remember
the details how it's done offhand though.
The only theoretical problem there was that the kernel still had a
cacheable mapping of the same memory, and any access via that (e.g.
prefetch due to access to a neighbouring page) could trigger a machine
check. But I don't remember ever hitting that. Maybe I was just lucky
all those years.
--
Earthling Michel Dänzer | https://redhat.com
Libre software enthusiast | Mesa and X developer
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-05-13 10:26 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 19:55 [RFC] Remove AGP support from Radeon/Nouveau/TTM John Paul Adrian Glaubitz
2020-05-11 20:05 ` Alex Deucher
2020-05-11 20:25 ` Rui Salvaterra
2020-05-11 20:51 ` Alex Deucher
2020-05-12 7:57 ` Michel Dänzer
2020-05-12 9:21 ` Rui Salvaterra
2020-05-12 9:40 ` Karoly Balogh (Charlie/SGR)
2020-05-12 13:22 ` Alex Deucher
2020-05-12 16:37 ` Daniel Vetter
2020-05-12 17:02 ` Rui Salvaterra
2020-05-12 18:21 ` Alex Deucher
2020-05-12 20:12 ` Dave Airlie
2020-05-13 7:26 ` Christian König
2020-05-12 18:22 ` Alex Deucher
2020-05-13 7:19 ` Daniel Vetter
2020-05-13 7:55 ` Christian König
2020-05-13 10:25 ` Daniel Vetter
2020-05-13 9:28 ` Rui Salvaterra
2020-05-13 10:26 ` Michel Dänzer [this message]
2020-05-13 10:29 ` Daniel Vetter
2020-05-13 10:32 ` Michel Dänzer
2020-05-13 10:39 ` Rui Salvaterra
2020-05-13 10:57 ` Michel Dänzer
2020-05-13 11:07 ` Rui Salvaterra
2020-05-13 13:44 ` Christian Zigotzky
2020-05-13 14:01 ` John Paul Adrian Glaubitz
2020-05-13 14:01 ` Rui Salvaterra
2020-05-13 20:19 ` Bertrand Dekoninck
2020-05-13 20:36 ` Rui Salvaterra
2020-05-11 20:41 ` John Paul Adrian Glaubitz
2020-05-11 20:46 ` Alex Deucher
2020-05-11 21:50 ` John Paul Adrian Glaubitz
2020-05-12 7:43 ` Christian König
2020-05-11 20:12 ` Christian König
2020-05-11 20:24 ` John Paul Adrian Glaubitz
2020-05-11 20:48 ` Gerhard Pircher
2020-05-12 5:04 ` David VANTYGHEM
2020-05-12 9:20 ` John Paul Adrian Glaubitz
-- strict thread matches above, loose matches on Subject: below --
2020-05-11 17:17 Christian König
2020-05-11 20:14 ` Al Dunsmuir
2020-05-11 20:27 ` Alex Deucher
2020-05-11 20:43 ` Dave Airlie
2020-05-11 20:56 ` Al Dunsmuir
2020-05-12 8:11 ` Christian König
2020-05-11 20:59 ` Emil Velikov
2020-05-11 20:46 ` Al Dunsmuir
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=69696543-7c0e-604d-ed29-721b1b99d44e@daenzer.net \
--to=michel@daenzer.net \
--cc=charlie@scenergy.dfmk.hu \
--cc=ckoenig.leichtzumerken@gmail.com \
--cc=daniel@ffwll.ch \
--cc=debian-powerpc@lists.debian.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=glaubitz@physik.fu-berlin.de \
--cc=rsalvaterra@gmail.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;
as well as URLs for NNTP newsgroup(s).