diff options
Diffstat (limited to 'arch/x86/kernel/i8259.c')
| -rw-r--r-- | arch/x86/kernel/i8259.c | 46 |
1 files changed, 34 insertions, 12 deletions
diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c index 15aefa3f3e18..2bade73f49e3 100644 --- a/arch/x86/kernel/i8259.c +++ b/arch/x86/kernel/i8259.c @@ -23,6 +23,7 @@ #include <asm/desc.h> #include <asm/apic.h> #include <asm/i8259.h> +#include <asm/io_apic.h> /* * This is the 'legacy' 8259A Programmable Interrupt Controller, @@ -32,6 +33,7 @@ */ static void init_8259A(int auto_eoi); +static bool pcat_compat __ro_after_init; static int i8259A_auto_eoi; DEFINE_RAW_SPINLOCK(i8259A_lock); @@ -114,6 +116,7 @@ static void make_8259A_irq(unsigned int irq) disable_irq_nosync(irq); io_apic_irqs &= ~(1<<irq); irq_set_chip_and_handler(irq, &i8259A_chip, handle_level_irq); + irq_set_status_flags(irq, IRQ_LEVEL); enable_irq(irq); lapic_assign_legacy_vector(irq, true); } @@ -230,9 +233,7 @@ struct irq_chip i8259A_chip = { }; static char irq_trigger[2]; -/** - * ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ - */ +/* ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ */ static void restore_ELCR(char *trigger) { outb(trigger[0], PIC_ELCR1); @@ -300,15 +301,32 @@ static void unmask_8259A(void) static int probe_8259A(void) { + unsigned char new_val, probe_val = ~(1 << PIC_CASCADE_IR); unsigned long flags; - unsigned char probe_val = ~(1 << PIC_CASCADE_IR); - unsigned char new_val; + /* - * Check to see if we have a PIC. - * Mask all except the cascade and read - * back the value we just wrote. If we don't - * have a PIC, we will read 0xff as opposed to the - * value we wrote. + * If MADT has the PCAT_COMPAT flag set, then do not bother probing + * for the PIC. Some BIOSes leave the PIC uninitialized and probing + * fails. + * + * Right now this causes problems as quite some code depends on + * nr_legacy_irqs() > 0 or has_legacy_pic() == true. This is silly + * when the system has an IO/APIC because then PIC is not required + * at all, except for really old machines where the timer interrupt + * must be routed through the PIC. So just pretend that the PIC is + * there and let legacy_pic->init() initialize it for nothing. + * + * Alternatively this could just try to initialize the PIC and + * repeat the probe, but for cases where there is no PIC that's + * just pointless. + */ + if (pcat_compat) + return nr_legacy_irqs(); + + /* + * Check to see if we have a PIC. Mask all except the cascade and + * read back the value we just wrote. If we don't have a PIC, we + * will read 0xff as opposed to the value we wrote. */ raw_spin_lock_irqsave(&i8259A_lock, flags); @@ -407,7 +425,7 @@ struct legacy_pic null_legacy_pic = { .make_irq = legacy_pic_uint_noop, }; -struct legacy_pic default_legacy_pic = { +static struct legacy_pic default_legacy_pic = { .nr_legacy_irqs = NR_IRQS_LEGACY, .chip = &i8259A_chip, .mask = mask_8259A_irq, @@ -430,5 +448,9 @@ static int __init i8259A_init_ops(void) return 0; } - device_initcall(i8259A_init_ops); + +void __init legacy_pic_pcat_compat(void) +{ + pcat_compat = true; +} |