Date: Mon, 28 May 2007 08:53:18 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: John-Mark Gurney <gurney_j@resnet.uoregon.edu> Cc: freebsd-usb@freebsd.org Subject: Re: 31st address line sometimes not used on EHCI/UHCI/OHCI Message-ID: <200705280853.18551.hselasky@c2i.net> In-Reply-To: <20070527215329.GY4602@funkthat.com> References: <200705272235.46048.hselasky@c2i.net> <20070527215329.GY4602@funkthat.com>
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On Sunday 27 May 2007 23:53, John-Mark Gurney wrote: > Hans Petter Selasky wrote this message on Sun, May 27, 2007 at 22:35 +0200: > > I've got some reports back that some USB host controllers do not support > > transferring memory from a location higher than 2GB. > > > > What should we do about this? > > > > Should we limit all USB DMA allocations to the lower 2GB of the memory? > > No, a quirk table should be setup and pass the restriction to bus_dma > at tag initalization time when a broken controller is detected.. Yes, I can do that. But I am also thinking about a static quirk, like a sysctl you can set at boot time. I hope that this is not a wide-spread problem. And I am not surprised that hardware manufacturers are not specification compliant, which really makes me wonder if they support a true 64-bit address bus on the EHCI controller at all. I would maybe cost too much money? And therefore we should just stick with 32-bit addressing on 32-bit platforms aswell. --HPS
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