From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benoit Boissinot Subject: Re: [RFC/PATCH] remove unneeded check in bcm43xx Date: Mon, 10 Apr 2006 06:22:28 +0200 Message-ID: <20060410042228.GN27596@ens-lyon.fr> References: <20060410040120.GA4860@ens-lyon.fr> <200604100607.33362.mb@bu3sch.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, bcm43xx-dev@lists.berlios.de, linux-kernel@vger.kernel.org, linville@tuxdriver.com, benh@kernel.crashing.org Return-path: To: Michael Buesch Content-Disposition: inline In-Reply-To: <200604100607.33362.mb@bu3sch.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Apr 10, 2006 at 06:07:32AM +0200, Michael Buesch wrote: > On Monday 10 April 2006 06:01, you wrote: > > Since the driver already sets the correct dma_mask, there is no reason > > to bail there. In fact if you have an iommu, I think you can have a > > address above 1G which will be ok for the device (if it isn't true then > > the powerpc dma_alloc_coherent with iommu needs to be fixed because it > > doesn't respect the the dma_mask). > > > > Please comment or apply. > > NACK. Don't apply that patch. > I know it is odd, but people are actually hitting these messages. > Maybe benh can explain the issues. I don't know... > Yes, I know they hit the message, that's from a message in some forum that i got interested in the issue. It probably comes from an allocation from: http://www.linux-m32r.org/lxr/http/source/arch/powerpc/kernel/pci_direct_iommu.c#L32 Either the ppc code is wrong (it doesn't enforce dma_mask) either the driver still works without the check. Maybe ppc should do the same thing as i386: 47 if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff)) 48 gfp |= GFP_DMA; thanks, Benoit -- powered by bash/screen/(urxvt/fvwm|linux-console)/gentoo/gnu/linux OS