On Wed, Sep 21, 2022 at 12:05:26AM +0000, Yoshihiro Shimoda wrote: > Hi Bjorn, > > Thank you for your review! > > > From: Bjorn Helgaas, Sent: Wednesday, September 21, 2022 5:08 AM > > > > On Mon, Sep 05, 2022 at 04:12:48PM +0900, Yoshihiro Shimoda wrote: > > > Add macros defining Maximum Link Width bits in Link Capabilities > > > Register. > > > > > > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> > > > --- > > > include/uapi/linux/pci_regs.h | 7 +++++++ > > > 1 file changed, 7 insertions(+) > > > > > > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h > > > index 57b8e2ffb1dd..c9f4c452e210 100644 > > > --- a/include/uapi/linux/pci_regs.h > > > +++ b/include/uapi/linux/pci_regs.h > > > @@ -538,6 +538,13 @@ > > > #define PCI_EXP_LNKCAP_SLS_16_0GB 0x00000004 /* LNKCAP2 SLS Vector bit 3 */ > > > #define PCI_EXP_LNKCAP_SLS_32_0GB 0x00000005 /* LNKCAP2 SLS Vector bit 4 */ > > > #define PCI_EXP_LNKCAP_SLS_64_0GB 0x00000006 /* LNKCAP2 SLS Vector bit 5 */ > > > +#define PCI_EXP_LNKCAP_MLW_X1 0x00000010 /* Maximum Link Width x1 */ > > > +#define PCI_EXP_LNKCAP_MLW_X2 0x00000020 /* Maximum Link Width x2 */ > > > +#define PCI_EXP_LNKCAP_MLW_X4 0x00000040 /* Maximum Link Width x4 */ > > > +#define PCI_EXP_LNKCAP_MLW_X8 0x00000080 /* Maximum Link Width x8 */ > > > +#define PCI_EXP_LNKCAP_MLW_X12 0x000000c0 /* Maximum Link Width x12 */ > > > +#define PCI_EXP_LNKCAP_MLW_X16 0x00000100 /* Maximum Link Width x16 */ > > > +#define PCI_EXP_LNKCAP_MLW_X32 0x00000200 /* Maximum Link Width x32 */ > > > > In PCIe r6.0, x32 is mentioned a few times, but not actually defined > > for Link Capabilities. Has it been defined in an ECN or something? > > I should have looked PCIe r6.0, but I looked PCIe r4.0 v1.0 and it mentioned x32. > So, I wrote the x32 macro. Sure enough. It's there in r4.0 and r5.0, but dropped from r6.0. Wish there were a git tree where we could see whether this was a mistake or there was some reason for it. Maybe nobody had actually built x32 hardware and they wanted to reserve the flexibility for something else. > I'll drop PCI_EXP_LNKCAP_MLW_X32 on v6 patch. When you do, add my: Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
