From: Paul Fulghum <paulkf@microgate.com>
To: "Burkhard Schölpen" <bschoelpen@web.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: PCI DMA burst delay
Date: Thu, 29 Dec 2005 09:23:01 -0600 [thread overview]
Message-ID: <43B3FF55.4050304@microgate.com> (raw)
In-Reply-To: <395333712@web.de>
Burkhard Schölpen wrote:
> ... in the (rarely) faulty case, the 2nd burst only starts
> after another delay of about 600ns, which is too late
Looking at the PCI 2.3 specification,
arbitration latency on the order of a microsecond
or two does not seem excessive for a 33MHz bus.
> ... I deactivated all other pci devices that could disturb the transfers?
Are you accessing registers on your device
during the DMA transfers? If so, the CPU is
acting as a PCI master that could delay granting
the bus to your device.
--
Paul Fulghum
Microgate Systems, Ltd.
next prev parent reply other threads:[~2005-12-29 15:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-29 14:43 PCI DMA burst delay Burkhard Schölpen
2005-12-29 15:23 ` Paul Fulghum [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-12-29 16:03 Burkhard Schölpen
2005-12-29 16:55 ` Paul Fulghum
[not found] <5p7gt-3lu-5@gated-at.bofh.it>
2005-12-29 18:40 ` Robert Hancock
2005-12-30 13:23 Burkhard Schölpen
2005-12-30 18:45 ` Robert Hancock
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=43B3FF55.4050304@microgate.com \
--to=paulkf@microgate.com \
--cc=bschoelpen@web.de \
--cc=linux-kernel@vger.kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox