Date: Tue, 23 Sep 2008 18:21:22 +0100 From: Gavin Atkinson <gavin@FreeBSD.org> To: John Baldwin <jhb@FreeBSD.org> Cc: freebsd-acpi@FreeBSD.org Subject: Re: Writing a driver: how do I get resources? Message-ID: <1222190482.80882.28.camel@buffy.york.ac.uk> In-Reply-To: <200809231037.00392.jhb@freebsd.org> References: <1222173505.80882.15.camel@buffy.york.ac.uk> <200809231037.00392.jhb@freebsd.org>
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On Tue, 2008-09-23 at 10:36 -0400, John Baldwin wrote: > On Tuesday 23 September 2008 08:38:25 am Gavin Atkinson wrote: > > Hi all, > > > > Please forgive me if this email makes very little sense: I've never > > really looked at how ACPI works from a driver's perspective, so don't > > really know if what I'm trying to do is even correct. > > > > I'm expanding the acpi_sony driver to cover the PNP ID SNY6001. When I > > simply claim it by returning 0 from the probe, I get the following I/O > range: > > > > acpi_sony0: <Sony programmable I/O> port 0-0x1f on acpi0 > > > > However, if I'm reading the AML[1] and Linux drivers[2] correctly, this > > is not the correct range. It appears that the _PRS method offers a > > choice of four I/O ranges and four IRQs, one of which is then selected > > by evaluating _SRS. None of them are 0-0x1f. > > > > Firstly, does that make sense? Secondly, how do I do this from a > > driver? I can't see any other drivers that seem to get this involved in > > ACPI, indeed the only mention of evaluating _PRS is within the ACPI code > > itself. > > > > Lastly, I only have intermittent access to this laptop, so I apologise > > if I can't test things quickly. > > Our ACPI driver isn't smart enough yet (AFAIK) to allocate new resources for a > device that doesn't have any. That logic should be in acpi_alloc_resource() > and once that is present then your driver just needs to do the usual > bus_alloc_resource() stuff to work. Thanks. So I guess there's no easy way to do it at the moment? Gavin
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