Date: Mon, 27 Oct 2008 09:07:28 -0700 From: Nate Lawson <nate@root.org> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-acpi@freebsd.org, Alexander Motin <mav@freebsd.org> Subject: Re: PCIe bridges resources disappearing with ACPI enabled. Message-ID: <4905E740.9060302@root.org> In-Reply-To: <200810271142.59666.jhb@freebsd.org> References: <4903A120.7040003@FreeBSD.org> <200810271142.59666.jhb@freebsd.org>
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John Baldwin wrote: > On Saturday 25 October 2008 06:43:44 pm Alexander Motin wrote: >> I have spent whole day trying to investigate strange problem of my Acer >> TM6292 laptop (965GM+ICH8M). When booted with ACPI enabled, all three >> of PCIe-to-PCIe bridges appearing completely without I/O resources: >> pcib1: <ACPI PCI-PCI bridge> irq 17 at device 28.0 on pci0 >> pcib1: domain 0 >> pcib1: secondary bus 2 >> pcib1: subordinate bus 3 >> pcib1: I/O decode 0x0-0x0 >> pcib1: no prefetched decode >> ... >> At the same time, with ACPI disabled, resources are present. There are >> some different problem with IRQ in that case, but it is another >> question, not so interesting to me. >> >> I have tried both IO and memory mapped PCIe configuration registers >> without success. >> >> I have made heavy digging trying to find where resources disappearing. I >> have even added debug printing inside pcireg_cfgwrite() and >> pciereg_cfgwrite() to trace if somebody erases it and found nothing. >> Nothing writes into that devices configuration registers. > > The SMI handler could be clearing the BARs when ACPI is enabled for some > reason. Windows and Linux are smart enough to alloc resources for bridges, > but FreeBSD isn't yet. That would match my expectations also. Where Linux works with ACPI but FreeBSD does not, it tends to be an error of omission (missing features) versus commission (a bug). So I would start looking into implementing more of the PCIe and ACPI spec. Look for areas where Linux has had more functionality brought in over the past couple years. -- Nate
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