Section 7.8.2 of the PCI Express specification (r4.0 v0.3), entitled "PCI
Express Capabilities Register (Offset 02h)", and section 7.8.9 "Slot
Capabilities Register (Offset 14h)" of the same, describe the conditions
when a PCIe port should be considered "supporting hotplug":
- it should be a root complex port or a switch downstream port, and
- it should have the "Slot Implemented" bit set in the Express
Capabilities Register, and
- it should have the "Hot-Plug Capable" bit set in the Slot Capabilities
Register.
The first two sub-conditions are already implemented in at least two open
source projects I could find:
- in SeaBIOS by Marcel Apfelbaum: "hw/pci: reserve IO and mem for pci
express downstream ports with no devices attached"
<https://code.coreboot.org/p/seabios/source/commit/3aa31d7d6375>,
- in edk2 itself, in the implementation of the "PCI" UEFI Shell command:
see the "PcieExplainTypeSlot" case label in function
PciExplainPciExpress(), file
"ShellPkg/Library/UefiShellDebug1CommandsLib/Pci.c".
PciBusDxe recognizes such PCIe ports as bridges, but it doesn't realize
they support hotplug. In turn PciBusDxe omits getting any resource padding
information from the platform's EFI_PCI_HOT_PLUG_INIT_PROTOCOL for these
bridges:
GatherPpbInfo() [PciEnumeratorSupport.c]
GetResourcePaddingPpb() [PciResourceSupport.c]
GetResourcePaddingForHpb() [PciHotPlugSupport.c]
IsPciHotPlugBus() [PciHotPlugSupport.c]
//
// returns FALSE
//
//
// the following is not reached:
//
gPciHotPlugInit->GetResourcePadding()
Implement a function called SupportsPcieHotplug() for identifying such
ports, and call it from IsPciHotPlugBus() (after the call to IsSHPC()).
Cc: "Johnson, Brian J." <bjohnson@sgi.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ruiyu Ni <Ruiyu.ni@intel.com>
This check-in fix the issue by adding a flag to indicate if a HPC is found during PCI enumeration or not. This check-in also adds a debug message if any found HPC failed with initialization.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11081 6f19259b-4bc3-4df7-8a09-765794883524
a. Update PciBusDxe module, and move it from IntelFrameworkModulePkg to MdeModulePkg
b. Move IncompatiblePciDeviceSupportDxe module from IntelFrameworkModulePkg to MdeModulePkg
c. Update the related consumes in inf/dsc/fdf
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9347 6f19259b-4bc3-4df7-8a09-765794883524
Michael D Kinney
Ray Ni
Laszlo Ersek
rsun3
hhtian
davidhuang