Date: Wed, 15 Jun 2011 14:52:09 -0400 From: John Baldwin <jhb@freebsd.org> To: Nate Lawson <nate@root.org> Cc: acpi@freebsd.org Subject: Re: Only attach device_t objects to ACPI devices with a _HID Message-ID: <201106151452.09955.jhb@freebsd.org> In-Reply-To: <DB0F2A34-C457-4372-8A20-1F32EE3A66BD@root.org> References: <201106150957.58049.jhb@freebsd.org> <DB0F2A34-C457-4372-8A20-1F32EE3A66BD@root.org>
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On Wednesday, June 15, 2011 12:48:09 pm Nate Lawson wrote: > On Jun 15, 2011, at 6:57 AM, John Baldwin wrote: > > What I am proposing to do is to change the ACPI bus driver to only add > > device_t objects for Device() nodes that have a _HID or _CID. This should not > > break any devices that have a current driver, but it will avoid having ACPI > > attach to PCI devices. This does mean that _CRS is currently ignored for PCI > > devices. My feeling on that is that if we do feel that is important to > > reserve those resources, we should handle that in the ACPI PCI bus driver > > itself instead (it can examine _CRS for those devices and allocate resources > > if we so choose). > > While this should be fine for legacy devices, I do worry about other synthetic devices, such as CPUs, NUMA zones, etc. Would it be better just not to attach acpi device_t's to any nodes under PCI busses? This is harder to arrange. Note that the proposed patch only applies to a Device(), not to Processor() or ThermalZone(), etc. objects. I believe though that all such things that you mentioned use either an object type other than ACPI_TYPE_DEVICE, an entirely different table (MADT, SRAT, etc.), or a Device() with a HID or CID. > Also, it's still possible some PCI devices would have a CID, so you'd still have to handle this case, right? Yes, and we already handle that case (there's an older tablet that hung a system resource device off its PCI-ISA bridge). In that case you still (as now) end up with two device_t's, one attached to acpi0, the other attached to the relevant PCI bus. -- John Baldwin
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