From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
To: "Måns Rullgård" <mru@users.sourceforge.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: USB and DMA on Alpha with 2.6.0-test7
Date: Fri, 10 Oct 2003 14:47:10 +0400 [thread overview]
Message-ID: <20031010144710.A1396@jurassic.park.msu.ru> (raw)
In-Reply-To: <yw1xu16hbg75.fsf@users.sourceforge.net>; from mru@users.sourceforge.net on Fri, Oct 10, 2003 at 11:22:06AM +0200
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.
next prev parent reply other threads:[~2003-10-10 10:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-10 9:22 Måns Rullgård
2003-10-10 10:47 ` Ivan Kokshaysky [this message]
2003-10-10 11:38 ` Måns Rullgård
2003-10-10 13:31 ` Jamie Lokier
2003-10-10 13:41 ` Ivan Kokshaysky
2003-10-10 16:41 ` Måns Rullgård
2003-10-10 17:18 David Brownell
2003-10-10 18:19 ` Ivan Kokshaysky
2003-10-10 18:45 ` Måns Rullgård
2003-10-10 18:59 ` Ivan Kokshaysky
2003-10-10 20:15 ` David Brownell
2003-10-10 19:43 ` David Brownell
2003-10-11 13:27 ` Ivan Kokshaysky
2003-10-11 16:26 ` David Brownell
2003-10-11 23:03 ` David Brownell
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