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From: Alan <alan@lxorguk.ukuu.org.uk>
To: Ray Lee <ray-lk@madrabbit.org>
Cc: Larry Finger <Larry.Finger@lwfinger.net>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Problem with DMA on x86_64 with 3 GB RAM
Date: Tue, 21 Nov 2006 11:28:29 +0000	[thread overview]
Message-ID: <20061121112829.19a9c043@localhost.localdomain> (raw)
In-Reply-To: <456282DE.1000407@madrabbit.org>

> Confused. As in, once the bcm43xx module initcall happens? Or without bcm43xx
> at all? If the former, is the behavior different when built as a module versus
> built-in? (ie, are there ordering problems.)

The pci_dma code on the x86_64 platform is broken for the case of PCI
devices with < 32bit DMA. Has been forever, this is a problem with
various devices, although most of the others are obsolete except for the
bcm43xx and b44 (the latter has hacks to work around the x86-64
brokenness).

At the very least the pci_set_dma_mask should error in this situation or
switch to using GFP_DMA (24bit) memory spaces. Having it error isn't the
whole solution as you still need some way to handle the "what do I do
next". 

Alan

  reply	other threads:[~2006-11-21 11:25 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-15 19:01 bcm43xx regression 2.6.19rc3 -> rc5, rtnl_lock trouble? Ray Lee
2006-11-15 19:15 ` Michael Buesch
2006-11-15 19:41   ` Ray Lee
2006-11-16  2:51     ` Larry Finger
2006-11-16  5:51       ` Ray Lee
2006-11-18 11:24 ` Joseph Fannin
2006-11-18 16:55   ` Johannes Berg
2006-11-18 17:05     ` Larry Finger
2006-11-18 17:27       ` Ray Lee
2006-11-18 18:30         ` Adrian Bunk
2006-11-21  6:21           ` Ray Lee
2006-11-18 19:02         ` Larry Finger
2006-11-19 16:01           ` Michael Buesch
2006-12-12  4:06           ` ieee80211 sleeping in invalid context Ray Lee
2006-12-12  9:14             ` Michael Buesch
2006-12-12 17:51               ` Ray Lee
2006-12-12 18:31                 ` Larry Finger
2006-11-19  6:15         ` Problem with DMA on x86_64 with 3 GB RAM Larry Finger
2006-11-21  4:38           ` Ray Lee
2006-11-21 11:28             ` Alan [this message]
2006-11-21 16:34               ` Larry Finger
2006-11-21 10:30           ` Andi Kleen
2006-11-21 16:37             ` Larry Finger
2006-11-21 16:46               ` Andi Kleen
2006-11-21 18:27                 ` Alan
2006-11-21 18:31                   ` Andi Kleen
2006-11-21 20:04                     ` Alan

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