Date: Fri, 25 Jul 2003 07:27:21 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: tlambert2@mindspring.com Cc: glastech@iinet.net.au Subject: Re: Probing for devices Message-ID: <20030725.072721.13038396.imp@bsdimp.com> In-Reply-To: <3F20D014.C421667@mindspring.com> References: <200307242017.29676.glastech@iinet.net.au> <3F20D014.C421667@mindspring.com>
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Geoff Glasson wrote: > I'm trying to port the Linux i810 Direct Rendering Interface ( DRI ) kernel > module to FreeBSD. I have reached the point where the thing compiles, and I > can load it as a kernel module, but it can't find the graphics device. > > Through a process of elimination I have come to the conclusion that once the > AGP kernel module probes and attaches to the i810 graphics device, nothing > else can attach to it. When I read the section on PCI devices it implied ( > to me at least ) that multiple kernel modules should be able to attach to the > same device. I have tried to get it to work without any success. You can't. One device cannot serve two master. The closest you can get is to create a bus device that then other drivers can attach to. The bus device can arbitrate access to the actual hardware. The second closest is if a chip has multiple functions, each of the functions can have their own driver. This is fairly fundamental to most operating systems. Warnerhome | help
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