On Mon, 2022-02-14 at 09:20 +0100, Geert Uytterhoeven wrote: > Hi Maciej, > > CC Niklas > > On Sun, Feb 13, 2022 at 1:45 PM Maciej W. Rozycki <macro@xxxxxxxxxxx> wrote: > > Nowadays PC-style parallel ports come in the form of PCI and PCIe option > > cards and there are some combined parallel/serial option cards as well > > that we handle in the parport subsystem. There is nothing in particular > > that would prevent them from being used in any system equipped with PCI > > or PCIe connectivity, except that we do not permit the PARPORT_PC config > > option to be selected for platforms for which ARCH_MIGHT_HAVE_PC_PARPORT > > has not been set for. > > > > The only PCI platforms that actually can't make use of PC-style parallel > > port hardware are those newer PCIe systems that have no support for I/O > > cycles in the host bridge, required by such parallel ports. An example > > of such a host bridge is the POWER9 PHB4 device, but it is an exception > > rather than the norm. Also it is not clear whether the serial port side > > Note that this hardware dependency is being addressed in > "[RFC 00/32] Kconfig: Introduce HAS_IOPORT and LEGACY_PCI options" > https://lore.kernel.org/all/20211227164317.4146918-1-schnelle@xxxxxxxxxxxxx/ Thanks, for Cc'ing me. Note that this series is currently in kind of a hold as we haven't yet found a clear direction yet. There was some clear opposition for the LEGACY_PCI option introduced in that series and only little support for HAS_IOPORT. > > > --- linux-macro.orig/drivers/parport/Kconfig > > +++ linux-macro/drivers/parport/Kconfig > > @@ -42,7 +42,7 @@ if PARPORT > > > > config PARPORT_PC > > tristate "PC-style hardware" > > - depends on ARCH_MIGHT_HAVE_PC_PARPORT > > + depends on ARCH_MIGHT_HAVE_PC_PARPORT || PCI This would allow selecting PARPORT_PC on s390 e.g. for allyesconfig and randconfig and like POWER9 we definitely do not support I/O port access. We will also get warnings when compiling with clang. A problem my series was originally started to address. So I'd really like to see a better solution here for such a change. With the HAS_IOPORT option from my series this would be simple but we don't currently have that though maybe this is also an argument for introducing HAS_IOPORT even if we don't add the LEGACY_PCI option. > > help > > You should say Y here if you have a PC-style parallel port. All > > IBM PC compatible computers and some Alphas have PC-style > > @@ -77,7 +77,7 @@ config PARPORT_PC_FIFO > > > > config PARPORT_PC_SUPERIO > > bool "SuperIO chipset support" > > - depends on PARPORT_PC && !PARISC > > + depends on ARCH_MIGHT_HAVE_PC_PARPORT && PARPORT_PC && !PARISC > > help > > Saying Y here enables some probes for Super-IO chipsets in order to > > find out things like base addresses, IRQ lines and DMA channels. It > > > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
