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
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