On 11/15/2024 2:47 AM, Lukas Wunner wrote: > On Thu, Nov 14, 2024 at 11:07:26AM -0600, Bowman, Terry wrote: >>> Can you have a CXL port that is not a CXL device? >>> >>> If not, it would seem to me that checking for Flexbus DVSEC presence >>> *is* redundant. Or do you anticipate broken devices which lack the >>> Flexbus DVSEC and that you explicitly want to exclude? >> No, the CXL port device is always a CXL device per spec. >> >> This was added to short-circuit the function by returning immediately >> if the device is _not_ a CXL device. Otherwise for PCIe Port devices, >> the CXL Port DVSEC will be searched. I was trying to avoid the unnecessary >> CXL port DVSEC search unless the other criteria are met. >> And I expect most cases will not be a CXL device. >> >> I will remove the "if (!pcie_is_cxl(dev))" block as you suggested. > Ah, this is meant as a speed-up. Actually that makes sense, > so feel free to keep it. > > If you do remove it, I think you'll have to move the cxl_port_dvsec() > invocation up in the function, in front of the pci_pcie_type() checks. > The latter require that one first checks that the device is PCIe. > That's done implicitly by cxl_port_dvsec() because it returns 0 in > the non-PCIe case. (Due to the "if (dev->cfg_size <= PCI_CFG_SPACE_SIZE)" > check in pci_find_next_ext_capability().) > > Another idea would be to put a "if (!pcie_is_cxl(dev)) return 0;" speed-up > in cxl_port_dvsec() so that the other caller benefits from it as well. > > Thanks, > > Lukas Ok, I'll look at adding the same pcie_is_cxl() call and check in cxl_port_devsec(). Regards, Terry
