On Wed, Sep 2, 2020 at 12:20 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > > Hi, > > On 9/2/20 5:34 PM, Peter Robinson wrote: > > On Wed, Sep 2, 2020 at 4:08 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > >> > >> Hi All, > >> > >> 5.8 introduces a new CONFIG_USB_XHCI_PCI_RENESAS Kconfig symbol. > >> > >> The current Fedora kernel config says this to 'm'. I assume that > >> this was done because the help-text suggests that doing so will > >> make support for some special XHCI controllers which need to > >> be "booted" (have firmware loaded) by the kernel modular, while > >> keeping the generic xhci-pci code builtin so that we start probing > >> XHCI USB busses ASAP during boot. > >> > >> But, and this is somewhat of a surprise, the xhci-pci-renesas > >> code does not use the xhci-pci code as a library on top of > >> which it builds. Instead it offers some hooks for the xhci-pci > >> code to call in and having CONFIG_USB_XHCI_PCI_RENESAS set will > >> thus make xhci-pci.ko depend on xhci-pci-renesas.ko. > >> > >> Which means that if xhci-pci-renesas.ko is not builtin, this > >> also forces xhci-pci.ko to not be builtin. > >> > >> As said I assume that this xhci-pci.ko no longer being builtin > >> is not intentional, so that the right way to fix this would > >> be to set CONFIG_USB_XHCI_PCI_RENESAS=y, right ? > > > > We don't need to enable CONFIG_USB_XHCI_PCI_RENESAS because we don't > > enable ARCH_RENESAS, if that controller has some weirdisms upstream > > likely should have made it something like "default y if ARCH_RENESAS" > > or similar. > > This is not about ARCH_RENESAS, RENESAS also makes standalone > PCI-e XHCI chips like: > > https://h-node.org/hostcontrollers/view/en/1627/Renesas-Technology-Corp--uPD720201-USB-3-0-Host-Controller--rev-03- > > I found this webpage by searching for one of the 2 PCI-ids which > use the new CONFIG_USB_XHCI_PCI_RENESAS code. > > It seems these are the same as the standalone Nec PCI-e XHCI > controllers, and these are used on PCI-e add-on cards like e.g.: > > https://www.newegg.ca/syba-model-sd-pex20139-pci-express-to-usb-card/p/N82E16815124120 > > I have a couple of these cards, including some models > using Nec chips, and they worked fine before this new > kernel support for firmware-loading. I guess that in > most cases they just boot of an external SPI flash which > these cards seem to have. > > So me might indeed still be fine with disabling this option, > but I wanted to make it clear that AFAICT this is not > related to ARCH_RENESAS being set or not. > > OTOH the xhci-pci-renesas.c file is tiny so just building > it in would not be a big deal. With that said, if we take > that approach to every Kconfig option a lot of small > bits of extra code do add up. So maybe we should indeed > disable it until someone comes along who actually needs it? > It is not a super common case that something like this comes along and needs to be inlined. I think we are okay. I will turn switch it for 5.8.6 when it comes out Justin _______________________________________________ kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx
