I agree with you about that fact😊 These "[1]" was added 6 years ago when "[0]" still caused compilation failure. Later, about 5 years ago, Mike enabled "[0]" with the below change in MdePkg/Include/Base.h:
// // Disable warning when last field of data structure is a zero sized array. // #pragma warning ( disable : 4200 ) We cannot change these "[1]" to "[0]" because that would cause existing code that depends on sizeof() result fails. But for new code, it's encouraged to use "[0]". Thanks, Ray > -----Original Message----- > From: Javeed, Ashraf <ashraf.jav...@intel.com> > Sent: Thursday, March 19, 2020 6:00 PM > To: Ni, Ray <ray...@intel.com>; Gao, Liming <liming....@intel.com>; Liu, > Zhiguang <zhiguang....@intel.com>; Kinney, > Michael D <michael.d.kin...@intel.com> > Cc: devel@edk2.groups.io > Subject: RE: [edk2-devel] [PATCH V2] MdePkg-PciExpress40.h: DVSEC definition > missing > > All the PCIe capability structures with the > PCI_EXPRESS_EXTENDED_CAPABILITIES_HEADER; that has variable length > features have been implemented in this way. I am counting around 12 > structures which have been defined in the same > way. > > > -----Original Message----- > > From: Ni, Ray <ray...@intel.com> > > Sent: Thursday, March 19, 2020 2:30 PM > > To: Javeed, Ashraf <ashraf.jav...@intel.com>; Gao, Liming > > <liming....@intel.com>; Liu, Zhiguang <zhiguang....@intel.com>; Kinney, > > Michael D <michael.d.kin...@intel.com> > > Cc: devel@edk2.groups.io > > Subject: RE: [edk2-devel] [PATCH V2] MdePkg-PciExpress40.h: DVSEC > > definition missing > > > > I am sorry I just noticed this patch. > > Is it better to have "DesignatedVendorSpecific[0]"? > > This will make the sizeof (structure) more accurate. > > > > > -----Original Message----- > > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of > > Javeed, > > > Ashraf > > > Sent: Tuesday, March 17, 2020 4:04 PM > > > To: devel@edk2.groups.io > > > Cc: Kinney, Michael D <michael.d.kin...@intel.com>; Gao, Liming > > > <liming....@intel.com>; Liu, Zhiguang <zhiguang....@intel.com> > > > Subject: [edk2-devel] [PATCH V2] MdePkg-PciExpress40.h: DVSEC > > > definition missing > > > > > > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2598 > > > > > > All registers definition of DVSEC are defined as per the PCI Express > > > Base Specification 4.0 chapter 7.9.6. > > > > > > Signed-off-by: Ashraf Javeed <ashraf.jav...@intel.com> > > > Cc: Michael D Kinney <michael.d.kin...@intel.com> > > > Cc: Liming Gao <liming....@intel.com> > > > Cc: Zhiguang Liu <zhiguang....@intel.com> > > > > > > V2: fixed the comment section description for DVSEC definitions > > > --- > > > MdePkg/Include/IndustryStandard/PciExpress40.h | 28 > > > ++++++++++++++++++++++++++++ > > > 1 file changed, 28 insertions(+) > > > > > > diff --git a/MdePkg/Include/IndustryStandard/PciExpress40.h > > > b/MdePkg/Include/IndustryStandard/PciExpress40.h > > > index 9d9b272546..0564d72861 100644 > > > --- a/MdePkg/Include/IndustryStandard/PciExpress40.h > > > +++ b/MdePkg/Include/IndustryStandard/PciExpress40.h > > > @@ -4,6 +4,7 @@ Support for the PCI Express 4.0 standard. > > > This header file may not define all structures. Please extend as > > > required. > > > > > > Copyright (c) 2018, American Megatrends, Inc. All rights > > > reserved.<BR> > > > +Copyright (c) 2020, Intel Corporation. All rights reserved.<BR> > > > SPDX-License-Identifier: BSD-2-Clause-Patent > > > > > > **/ > > > @@ -78,6 +79,33 @@ typedef struct { > > > } PCI_EXPRESS_EXTENDED_CAPABILITIES_PHYSICAL_LAYER_16_0; > > > ///@} > > > > > > +/// The Designated Vendor Specific Capability definitions /// Based > > > +on section 7.9.6 of PCI Express Base Specification 4.0. > > > +///@{ > > > +typedef union { > > > + struct { > > > + UINT32 DvsecVendorId : 16; > > > //bit 0..15 > > > + UINT32 DvsecRevision : 4; > > > //bit 16..19 > > > + UINT32 DvsecLength : 12; > > > //bit 20..31 > > > + }Bits; > > > + UINT32 Uint32; > > > +}PCI_EXPRESS_DESIGNATED_VENDOR_SPECIFIC_HEADER_1; > > > + > > > +typedef union { > > > + struct { > > > + UINT16 DvsecId : 16; > > > //bit 0..15 > > > + }Bits; > > > + UINT16 Uint16; > > > +}PCI_EXPRESS_DESIGNATED_VENDOR_SPECIFIC_HEADER_2; > > > + > > > +typedef struct { > > > + PCI_EXPRESS_EXTENDED_CAPABILITIES_HEADER Header; > > > + PCI_EXPRESS_DESIGNATED_VENDOR_SPECIFIC_HEADER_1 > > > DesignatedVendorSpecificHeader1; > > > + PCI_EXPRESS_DESIGNATED_VENDOR_SPECIFIC_HEADER_2 > > > DesignatedVendorSpecificHeader2; > > > + UINT8 > > > DesignatedVendorSpecific[1]; > > > > > +}PCI_EXPRESS_EXTENDED_CAPABILITIES_DESIGNATED_VENDOR_SPECIFIC; > > > +///@} > > > + > > > #pragma pack() > > > > > > #endif > > > -- > > > 2.21.0.windows.1 > > > > > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#55991): https://edk2.groups.io/g/devel/message/55991 Mute This Topic: https://groups.io/mt/72019653/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
