On Thu, 2024-05-23 at 03:11 +0100, Maciej W. Rozycki wrote: > On Fri, 5 Apr 2024, Niklas Schnelle wrote: > > > diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c > > index 0d35c77fad9e..38ac5236d2ea 100644 > > --- a/drivers/tty/serial/8250/8250_pci.c > > +++ b/drivers/tty/serial/8250/8250_pci.c > > @@ -928,6 +928,7 @@ static int pci_netmos_init(struct pci_dev *dev) > > return num_serial; > > } > > > > +#ifdef CONFIG_HAS_IOPORT > > /* > > * These chips are available with optionally one parallel port and up to > > * two serial ports. Unfortunately they all have the same product id. > [...] > > diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig > > index 47ff50763c04..54bf98869abf 100644 > > --- a/drivers/tty/serial/8250/Kconfig > > +++ b/drivers/tty/serial/8250/Kconfig > > @@ -136,7 +135,7 @@ config SERIAL_8250_PCILIB > > > > config SERIAL_8250_PCI > > tristate "8250/16550 PCI device support" > > - depends on SERIAL_8250 && PCI > > + depends on SERIAL_8250 && PCI && HAS_IOPORT > > select SERIAL_8250_PCILIB > > default SERIAL_8250 > > help > > This is clearly wrong, there is PCIe 8250 serial hardware that does MMIO > only, so the option has to stay possible to enable. I have such hardware > as shown in this log: > > Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled > serial 0001:01:00.0: enabling device (0140 -> 0142) > serial 0001:01:00.0: detected caps 00000700 should be 00000500 > 0001:01:00.0: ttyS0 at MMIO 0x600c080401000 (irq = 40, base_baud = 15625000) is a 16C950/954 > serial 0001:01:00.0: detected caps 00000700 should be 00000500 > 0001:01:00.0: ttyS1 at MMIO 0x600c080401200 (irq = 40, base_baud = 15625000) is a 16C950/954 > > which is from a POWER9 system. Which as you may know has no PCI port I/O > support in hardware, so it is quite relevant here. I'd like to keep this > PCIe serial option functional with my system. > > Also your change itself modifies 8250_pci.c (cited above for reference), > which would make no sense if SERIAL_8250_PCI was permanently disabled for > !HAS_IOPORT. Shall I take it than that the Kconfig change I question has > been made merely by mistake? > > Maciej Hi Maciej, With 2 more HAS_IOPORT patches having gone into v6.12-rc1 I'm looking at what's left and we're down to 4 prerequisite patches[0] before being able to compile-time disable inb()/outb()/…. This one being by far the largest of these. Looking at your suggestion it seems that to compile 8250_pci.c without HAS_IOPORT I'll have to add #ifdef CONFIG_HAS_IOPORT around the MOXI section as that uses I/O ports unconditionally. The rest seems fine and I guess would theoretically work on a system with !HAS_IOPORT. I'll send a v2 with that included. Note however that even though your POWER9 system does not have I/O port support in hardware we still have HAS_IOPORT enabled for arch/powerpc if PCI is enabed so even with this patch as is your POWER9 system should not be affected. Thanks, Niklas [0] https://git.kernel.org/pub/scm/linux/kernel/git/niks/linux.git/log/?h=has_ioport
