From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262009AbTJJKrg (ORCPT ); Fri, 10 Oct 2003 06:47:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262030AbTJJKrg (ORCPT ); Fri, 10 Oct 2003 06:47:36 -0400 Received: from jurassic.park.msu.ru ([195.208.223.243]:3082 "EHLO jurassic.park.msu.ru") by vger.kernel.org with ESMTP id S262009AbTJJKrf (ORCPT ); Fri, 10 Oct 2003 06:47:35 -0400 Date: Fri, 10 Oct 2003 14:47:10 +0400 From: Ivan Kokshaysky To: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= Cc: linux-kernel@vger.kernel.org Subject: Re: USB and DMA on Alpha with 2.6.0-test7 Message-ID: <20031010144710.A1396@jurassic.park.msu.ru> References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.2.5i In-Reply-To: ; from mru@users.sourceforge.net on Fri, Oct 10, 2003 at 11:22:06AM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 10, 2003 at 11:22:06AM +0200, Måns Rullgård wrote: > Yesterday, I compiled 2.6.0-test7 for one of my Alpha boxes. I have > an AX8817X based USB ethernet adaptor connected to it (it's short on > PCI slots), so I compiled the usbnet module. When I loaded usbnet, I > got a BUG at include/asm-generic/dma-mapping.h:19. Apparently, DMA > setup only works with PCI here. How should this be fixed? It worked > with -test4, albeit slowly, for other reasons. Well, the usage of dma_supported() in usbnet.c is wrong even for i386. USB device doesn't do DMA, it's USB controller what does. The driver should check dma_mask of the parent device instead, something like this: // possible with some EHCI controllers if (*udev->dev->parent->dma_mask == 0xffffffffffffffffULL) net->features |= NETIF_F_HIGHDMA; Ivan.