From: Johannes Berg <johannes@sipsolutions.net>
To: Peter Oh <poh@qca.qualcomm.com>
Cc: linux-wireless@vger.kernel.org, Bob Copeland <me@bobcopeland.com>,
ath10k@lists.infradead.org
Subject: Re: [PATCH] ath10k: Replace ioread with wmb for data sync
Date: Wed, 28 Jan 2015 08:37:23 +0100 [thread overview]
Message-ID: <1422430643.1973.1.camel@sipsolutions.net> (raw)
In-Reply-To: <54C875FD.3070101@qca.qualcomm.com> (sfid-20150128_064104_435635_7E681844)
On Tue, 2015-01-27 at 21:39 -0800, Peter Oh wrote:
> > Ok, sure, but I/O ordering two different writes, and ensuring device
> > has seen a posted write, are related but different things, no?
> yes, they are different and wmb guarantees both.
No, wmb() doesn't. I'd be very surprised if it had any side effect on
the PCI bus even on ARM. Read Documentation/memory-barriers.txt.
And to understand (PCI) posted writes, wikipedia helps:
http://en.wikipedia.org/wiki/Posted_write
johannes
_______________________________________________
ath10k mailing list
ath10k@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/ath10k
WARNING: multiple messages have this Message-ID (diff)
From: Johannes Berg <johannes@sipsolutions.net>
To: Peter Oh <poh@qca.qualcomm.com>
Cc: Bob Copeland <me@bobcopeland.com>,
ath10k@lists.infradead.org, linux-wireless@vger.kernel.org
Subject: Re: [PATCH] ath10k: Replace ioread with wmb for data sync
Date: Wed, 28 Jan 2015 08:37:23 +0100 [thread overview]
Message-ID: <1422430643.1973.1.camel@sipsolutions.net> (raw)
In-Reply-To: <54C875FD.3070101@qca.qualcomm.com> (sfid-20150128_064104_435635_7E681844)
On Tue, 2015-01-27 at 21:39 -0800, Peter Oh wrote:
> > Ok, sure, but I/O ordering two different writes, and ensuring device
> > has seen a posted write, are related but different things, no?
> yes, they are different and wmb guarantees both.
No, wmb() doesn't. I'd be very surprised if it had any side effect on
the PCI bus even on ARM. Read Documentation/memory-barriers.txt.
And to understand (PCI) posted writes, wikipedia helps:
http://en.wikipedia.org/wiki/Posted_write
johannes
next prev parent reply other threads:[~2015-01-28 7:37 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-26 22:25 [PATCH] ath10k: Replace ioread with wmb for data sync Peter Oh
2015-01-26 22:25 ` Peter Oh
2015-01-27 21:33 ` Bob Copeland
2015-01-27 21:33 ` Bob Copeland
2015-01-27 23:53 ` Peter Oh
2015-01-27 23:53 ` Peter Oh
2015-01-28 4:30 ` Bob Copeland
2015-01-28 4:30 ` Bob Copeland
2015-01-28 5:39 ` Peter Oh
2015-01-28 5:39 ` Peter Oh
2015-01-28 7:37 ` Johannes Berg [this message]
2015-01-28 7:37 ` Johannes Berg
2015-01-30 22:53 ` Peter Oh
2015-01-30 22:53 ` Peter Oh
2015-01-31 1:16 ` Sujith Manoharan
2015-01-31 1:16 ` Sujith Manoharan
2015-01-31 1:56 ` Peter Oh
2015-01-31 1:56 ` Peter Oh
2015-01-31 2:06 ` Sujith Manoharan
2015-01-31 2:06 ` Sujith Manoharan
2015-02-02 17:25 ` Peter Oh
2015-02-02 17:25 ` Peter Oh
2015-02-02 22:26 ` Adrian Chadd
2015-02-02 22:26 ` Adrian Chadd
2015-02-02 23:04 ` Peter Oh
2015-02-02 23:04 ` Peter Oh
2015-02-02 13:02 ` Johannes Berg
2015-02-02 13:02 ` Johannes Berg
2015-02-02 17:33 ` Peter Oh
2015-02-02 17:33 ` Peter Oh
2015-02-02 18:54 ` Johannes Berg
2015-02-02 18:54 ` Johannes Berg
2015-02-02 19:15 ` Peter Oh
2015-02-02 19:15 ` Peter Oh
2015-02-02 19:22 ` Johannes Berg
2015-02-02 19:22 ` Johannes Berg
2015-02-02 19:36 ` Peter Oh
2015-02-02 19:36 ` Peter Oh
2015-02-02 19:47 ` Johannes Berg
2015-02-02 19:47 ` Johannes Berg
2015-02-02 22:06 ` Peter Oh
2015-02-02 22:06 ` Peter Oh
2015-02-02 22:15 ` Peter Oh
2015-02-02 23:25 ` Florian Fainelli
2015-02-02 23:25 ` Florian Fainelli
2015-02-02 23:49 ` Peter Oh
2015-02-02 23:49 ` Peter Oh
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=1422430643.1973.1.camel@sipsolutions.net \
--to=johannes@sipsolutions.net \
--cc=ath10k@lists.infradead.org \
--cc=linux-wireless@vger.kernel.org \
--cc=me@bobcopeland.com \
--cc=poh@qca.qualcomm.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.