From: Bjorn Helgaas This series converts i386 and x86_64 legacy serial ports to be platform devices and prevents probing for them if we have PNP. This prevents double discovery, where a device was found both by the legacy probe and by 8250_pnp. This also prevents the serial driver from claiming IRDA devices (unless they have a UART PNP ID). The serial legacy probe sometimes assumed the wrong IRQ, so the user had to use "setserial" to fix it. Removing the need for setserial to make IRDA devices work seems good, but it does break some things. In particular, you may need to keep setserial from poking legacy UART stuff back in by doing something like "dpkg-reconfigure setserial" with the "kernel" option. Otherwise, the setserial-discovered "UART" will claim resources and prevent the IRDA driver from loading. This patch: If we can discover devices using PNP, we can skip some legacy probes. This flag ("pnp_platform_devices") indicates that PNPBIOS or PNPACPI is enabled and should tell us about builtin devices. Signed-off-by: Bjorn Helgaas Cc: Keith Owens Cc: Len Brown Cc: Adam Belay Cc: Matthieu CASTET Cc: Jean Tourrilhes Cc: Matthew Garrett Cc: Ville Syrjala Cc: Russell King Cc: Samuel Ortiz Signed-off-by: Andrew Morton --- drivers/pnp/core.c | 8 ++++++++ drivers/pnp/pnpacpi/core.c | 1 + drivers/pnp/pnpbios/core.c | 1 + include/linux/pnp.h | 2 ++ 4 files changed, 12 insertions(+) diff -puN drivers/pnp/core.c~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi drivers/pnp/core.c --- a/drivers/pnp/core.c~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi +++ a/drivers/pnp/core.c @@ -23,6 +23,14 @@ static LIST_HEAD(pnp_protocols); LIST_HEAD(pnp_global); DEFINE_SPINLOCK(pnp_lock); +/* + * ACPI or PNPBIOS should tell us about all platform devices, so we can + * skip some blind probes. ISAPNP typically enumerates only plug-in ISA + * devices, not built-in things like COM ports. + */ +int pnp_platform_devices; +EXPORT_SYMBOL(pnp_platform_devices); + void *pnp_alloc(long size) { void *result; diff -puN drivers/pnp/pnpacpi/core.c~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi drivers/pnp/pnpacpi/core.c --- a/drivers/pnp/pnpacpi/core.c~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi +++ a/drivers/pnp/pnpacpi/core.c @@ -285,6 +285,7 @@ static int __init pnpacpi_init(void) acpi_get_devices(NULL, pnpacpi_add_device_handler, NULL, NULL); pnp_info("PnP ACPI: found %d devices", num); unregister_acpi_bus_type(&acpi_pnp_bus); + pnp_platform_devices = 1; return 0; } subsys_initcall(pnpacpi_init); diff -puN drivers/pnp/pnpbios/core.c~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi drivers/pnp/pnpbios/core.c --- a/drivers/pnp/pnpbios/core.c~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi +++ a/drivers/pnp/pnpbios/core.c @@ -570,6 +570,7 @@ static int __init pnpbios_init(void) /* scan for pnpbios devices */ build_devlist(); + pnp_platform_devices = 1; return 0; } diff -puN include/linux/pnp.h~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi include/linux/pnp.h --- a/include/linux/pnp.h~pnp-notice-whether-we-have-pnp-devices-pnpbios-or-pnpacpi +++ a/include/linux/pnp.h @@ -364,6 +364,7 @@ int pnp_add_device(struct pnp_dev *dev); int pnp_device_attach(struct pnp_dev *pnp_dev); void pnp_device_detach(struct pnp_dev *pnp_dev); extern struct list_head pnp_global; +extern int pnp_platform_devices; /* multidevice card support */ int pnp_add_card(struct pnp_card *card); @@ -411,6 +412,7 @@ static inline int pnp_init_device(struct static inline int pnp_add_device(struct pnp_dev *dev) { return -ENODEV; } static inline int pnp_device_attach(struct pnp_dev *pnp_dev) { return -ENODEV; } static inline void pnp_device_detach(struct pnp_dev *pnp_dev) { ; } +#define pnp_platform_devices 0 /* multidevice card support */ static inline int pnp_add_card(struct pnp_card *card) { return -ENODEV; } _