On Wed, Feb 3, 2021 at 9:36:54, Lukas Wunner <lukas@xxxxxxxxx> wrote: > On Wed, Feb 03, 2021 at 09:11:03AM +0000, Gustavo Pimentel wrote: > > On Wed, Feb 3, 2021 at 7:51:3, Lukas Wunner <lukas@xxxxxxxxx> wrote: > > > On Wed, Feb 03, 2021 at 01:54:49AM +0000, Gustavo Pimentel wrote: > > > > On Tue, Feb 2, 2021 at 18:8:55, Lukas Wunner <lukas@xxxxxxxxx> wrote: > > > > > As the name implies, the capability is "vendor-specific", so it is > > > > > perfectly possible that two vendors use the same VSEC ID for different > > > > > things. > > > > > > > > > > To make sure you're looking for the right capability, you need to pass > > > > > a u16 vendor into this function and bail out if dev->vendor is > > > > > different. > > > > > > > > This function will be called by the driver that will pass the correct > > > > device which will be already pointing to the config space associated with > > > > the endpoint for instance. Because the driver is already attached to the > > > > endpoint through the vendor ID and device ID specified, there is no need > > > > to do that validation, it will be redundant. > > > > > > Okay. Please amend the kernel-doc to make it explicit that it's the > > > caller's responsibility to check the vendor ID. > > > > I don't think that would be necessary, as I said, the 'struct pci_dev *' > > already points exclusively for the device' config space, which contains > > all the capabilities for that particular device by his turn will be > > attached to a specific driver by the Vendor and Device IDs to a specific > > driver, that will know, firstly search for the specific device vendor ID, > > and then secondly how to decode it, and thirdly to do something with it. > > The helper you're adding may not only be called from drivers but also > from generic PCI code (such as set_pcie_thunderbolt()). In that case > the vendor ID is arbitrary. Also, it doesn't *hurt* documenting this > requirement, does it? I understand now your PoV. In that case, I can add that info to the function comment. > > Thanks, > > Lukas
