From: Roland Dreier <roland@topspin.com>
To: Dan Malek <dan@embeddededge.com>
Cc: Joakim Tjernlund <Joakim.Tjernlund@lumentis.se>,
Linuxppc-Embedded <linuxppc-embedded@lists.linuxppc.org>
Subject: Re: question on howto use invalidate_dcache_range
Date: 13 Mar 2003 10:19:07 -0800 [thread overview]
Message-ID: <52k7f3t9ic.fsf@topspin.com> (raw)
In-Reply-To: <3E70C88B.70004@embeddededge.com>
Joakim> Yes, but you still need to invalidate the buffer before
Joakim> also or invalidate it when the buffer is freed which may
Joakim> be possible if you are using your own buffer mgmt.
Dan> Why?
Is the following not possible:
CPU has a dirty cache line inside the buffer
Driver tells device to start DMA
Device finishes DMA
CPU writes back dirty cache line
Driver gets notification that DMA completed
Driver invalidates cache for buffer
The invalidate above is too late: the data is already corrupted by the
write back of the dirty cache.
- Roland
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2003-03-13 18:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-12 11:20 question on howto use invalidate_dcache_range Stephan Linke
2003-03-13 7:40 ` Joakim Tjernlund
2003-03-13 11:00 ` Stephan Linke
2003-03-13 13:24 ` Joakim Tjernlund
2003-03-13 15:04 ` Stephan Linke
2003-03-13 16:27 ` Dan Malek
2003-03-13 17:54 ` Joakim Tjernlund
2003-03-13 18:06 ` Dan Malek
2003-03-13 18:19 ` Roland Dreier [this message]
2003-03-13 18:39 ` Dan Malek
2003-03-13 19:09 ` Roland Dreier
2003-03-13 21:54 ` Joakim Tjernlund
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=52k7f3t9ic.fsf@topspin.com \
--to=roland@topspin.com \
--cc=Joakim.Tjernlund@lumentis.se \
--cc=dan@embeddededge.com \
--cc=linuxppc-embedded@lists.linuxppc.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 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.