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From: Andi Kleen <ak@suse.de>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Ray Lee <ray-lk@madrabbit.org>, linux-kernel@vger.kernel.org
Subject: Re: Problem with DMA on x86_64 with 3 GB RAM
Date: 21 Nov 2006 11:30:00 +0100	[thread overview]
Message-ID: <p73psbhay8n.fsf@bingen.suse.de> (raw)
In-Reply-To: <455FF672.4070502@lwfinger.net>

Larry Finger <Larry.Finger@lwfinger.net> writes:

> I am trying to debug a bcm43xx DMA problem on an x86_64 system with 3
> GB RAM. Depending on the particular chip and its implementation, dma
> transfers may use 64-, 32-, or 30-bit addressing, with the problem
> interface using 30-bit addressing. From test prints, the correct mask
> (0x3FFFFFFF) is supplied to pci_set_dma_mask and
> pci_set_consistent_dma_mask. Neither call returns an error. In
> addition, several x86_64 systems with more than 1 GB RAM have worked
> with the current code.

30bit DMA has be bounced through GFP_DMA. The driver needs special
code for this. You can look at the b44 driver for a working reference.

The pci_dma_* interfaces on x86-64 only support masks >= 0xffffffff,
anything smaller has to be handled manually.

-Andi

  parent reply	other threads:[~2006-11-21 10:30 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
2006-11-21 16:34               ` Larry Finger
2006-11-21 10:30           ` Andi Kleen [this message]
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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