From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============5555541484093426592==" MIME-Version: 1.0 From: Moore, Robert Subject: Re: [Devel] Error in documentation of AcpiOsDerivePciId? Date: Wed, 04 Aug 2010 14:36:35 -0700 Message-ID: <4911F71203A09E4D9981D27F9D830858AC59CE99@orsmsx503.amr.corp.intel.com> In-Reply-To: 4C555B05.9020708@s-t.de List-ID: To: devel@acpica.org --===============5555541484093426592== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Yes, there is a reason for ACPI_PCI_ID **. >From the ACPI Component Architecture User Guide and Programmer Reference: AcpiOsDerivePciId ----------------- PciId = Input: The full PCI ID (The full PCI configuration space address, consistin= g of a segment number, bus number, device number, and function number) as o= btained from control methods within the BIOS ACPI tables. Output: Where the derived PCI ID is returned. Some or all of the PCI ID sub= fields may be updated by this function. This function derives a full PCI ID for a PCI device, consisting of a Segme= nt number, a Bus number, and a Device number. The PCI hardware dynamically configures PCI bus numbers depending on the bu= s topology discovered during system initialization. The AcpiOsDerivePciId f= unction is invoked by the ACPICA subsystem during configuration of a PCI_Co= nfig Operation Region in order to (possibly) update the Bus number in the P= ciId with the actual Bus number as determined by the hardware and operating= system configuration. The PciId parameter is initially populated by the ACPICA subsystem during t= he Operation Region initialization. ACPICA then calls AcpiOsDerivePciId, wh= ich is expected to make any necessary modifications to the Segment, Bus, or= Device number PCI ID subfields as appropriate for the current hardware and= OS configuration. >-----Original Message----- >From: devel-bounces(a)acpica.org [mailto:devel-bounces(a)acpica.org] On Be= half >Of Rudi >Sent: Sunday, August 01, 2010 4:31 AM >Cc: devel(a)acpica.org >Subject: Re: [Devel] Error in documentation of AcpiOsDerivePciId? > >Hi all, > >is that still in the agenda ? Also, what is the reason why the last >parameter of AcpiOsDerivePciId() is "ACPI_PCI_ID **" and not just >"ACPI_PCI_ID *" ? Are there any situations, where AcpiOsDerivePciId >would want to reallocate PciId ? > > > > >Lin Ming wrote: >> 2010/4/22 Gr=C3=A9goire Sutre : >>> Hi Lin, >>> >>> Many thanks for your explanantion, I understand now why the second >>> argument passed to AcpiOsDerivePciId is a handle to the (PCI_Config) >>> operation region. >>> >>> But regarding the first argument of AcpiOsDerivePciId: the ACPICA >>> programmer reference says that: it is a handle to _the PCI device_. >>> >>> My question is: which PCI device? >>> >>> In my (possibly wrong) interpretation of the documentation, _the PCI >>> device_ is the device for which AcpiOsDerivePciId shall return an >>> updated Pci id. >>> >>> However, as far as I understand the code of AcpiEvPciConfigRegionSetup >>> (in file evrgnini.c), _the PCI device_ turns out to be an ancestor of >>> the device for which AcpiOsDerivePciId shall return an updated Pci id. >>> This ancestor being the upstream PCI root bridge (or the ACPI root node >>> if none was found). This interpretation of _the PCI device_ is also >>> consistent with my understanding of the Linux implementation of >>> AcpiOsDerivePciId, which finds the updated PCI id by ``traversing'' the >>> PCI-to-PCI bridges that are on the branch from AcpiOsDerivePciId's first >>> argument to its second argument. >> >> You are right, the first argument is the PCI root node. >> We may need to update the doc to figure out this. >> >> Thanks, >> Lin Ming >> _______________________________________________ >> Devel mailing list >> Devel(a)acpica.org >> http://lists.acpica.org/listinfo/devel >> >> To: gregoire.sutre(a)gmail.com >> Cc: devel(a)acpica.org > >-- > >Ruediger "Rudi" Ihle > >"There's a fine line between wrong and visionary. Unfortunately > you have to be a visionary to see it." - Sheldon Cooper, Ph.D. >_______________________________________________ >Devel mailing list >Devel(a)acpica.org >http://lists.acpica.org/listinfo/devel --===============5555541484093426592==--