/* * pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $) * * Copyright (C) 2001, 2002 Andy Grover * Copyright (C) 2001, 2002 Paul Diefenbaugh * Copyright (C) 2002 Dominik Brodowski * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * TBD: * 1. Support more than one IRQ resource entry per link device (index). * 2. Implement start/stop mechanism and use ACPI Bus Driver facilities * for IRQ management (e.g. start()->_SRS). */ #include #include #include #include #include #include #include #include #include #include #include #include #define PREFIX "ACPI: " #define _COMPONENT ACPI_PCI_COMPONENT ACPI_MODULE_NAME("pci_link"); #define ACPI_PCI_LINK_CLASS "pci_irq_routing" #define ACPI_PCI_LINK_DEVICE_NAME "PCI Interrupt Link" #define ACPI_PCI_LINK_FILE_INFO "info" #define ACPI_PCI_LINK_FILE_STATUS "state" #define ACPI_PCI_LINK_MAX_POSSIBLE 16 static int acpi_pci_link_add(struct acpi_device *device); static int acpi_pci_link_remove(struct acpi_device *device, int type); static const struct acpi_device_id link_device_ids[] = { {"PNP0C0F", 0}, {"", 0}, }; MODULE_DEVICE_TABLE(acpi, link_device_ids); static struct acpi_driver acpi_pci_link_driver = { .name = "pci_link", .class = ACPI_PCI_LINK_CLASS, .ids = link_device_ids, .ops = { .add = acpi_pci_link_add, .remove = acpi_pci_link_remove, }, }; /* * If a link is initialized, we never change its active and initialized * later even the link is disable. Instead, we just repick the active irq */ struct acpi_pci_link_irq { u8 active; /* Current IRQ */ u8 triggering; /* All IRQs */ u8 polarity; /* All IRQs */ u8 resource_type; u8 possible_count; u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE]; u8 initialized:1; u8 reserved:7; }; struct acpi_pci_link { struct list_head list; struct acpi_device *device; struct acpi_pci_link_irq irq; int refcnt; }; static LIST_HEAD(acpi_link_list); static DEFINE_MUTEX(acpi_link_lock); /* -------------------------------------------------------------------------- PCI Link Device Management -------------------------------------------------------------------------- */ /* * set context (link) possible list from resource list */ static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource, void *context) { struct acpi_pci_link *link = context; u32 i; switch (resource->type) { case ACPI_RESOURCE_TYPE_START_DEPENDENT: case ACPI_RESOURCE_TYPE_END_TAG: return AE_OK; case ACPI_RESOURCE_TYPE_IRQ: { struct acpi_resource_irq *p = &resource->data.irq; if (!p || !p->interrupt_count) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Blank _PRS IRQ resource\n")); return AE_OK; } for (i = 0; (i < p->interrupt_count && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) { if (!p->interrupts[i]) { printk(KERN_WARNING PREFIX "Invalid _PRS IRQ %d\n", p->interrupts[i]); continue; } link->irq.possible[i] = p->interrupts[i]; link->irq.possible_count++; } link->irq.triggering = p->triggering; link->irq.polarity = p->polarity; link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ; break; } case ACPI_RESOURCE_TYPE_EXTENDED_IRQ: { struct acpi_resource_extended_irq *p = &resource->data.extended_irq; if (!p || !p->interrupt_count) { printk(KERN_WARNING PREFIX "Blank _PRS EXT IRQ resource\n"); return AE_OK; } for (i = 0; (i < p->interrupt_count && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) { if (!p->interrupts[i]) { printk(KERN_WARNING PREFIX "Invalid _PRS IRQ %d\n", p->interrupts[i]); continue; } link->irq.possible[i] = p->interrupts[i]; link->irq.possible_count++; } link->irq.triggering = p->triggering; link->irq.polarity = p->polarity; link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ; break; } default: printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n", resource->type); return AE_OK; } return AE_CTRL_TERMINATE; } static int acpi_pci_link_get_possible(struct acpi_pci_link *link) { acpi_status status; status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS, acpi_pci_link_check_possible, link); if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS")); return -ENODEV; } ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d possible IRQs\n", link->irq.possible_count)); return 0; } static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource, void *context) { int *irq = context; switch (resource->type) { case ACPI_RESOURCE_TYPE_START_DEPENDENT: case ACPI_RESOURCE_TYPE_END_TAG: return AE_OK; case ACPI_RESOURCE_TYPE_IRQ: { struct acpi_resource_irq *p = &resource->data.irq; if (!p || !p->interrupt_count) { /* * IRQ descriptors may have no IRQ# bits set, * particularly those those w/ _STA disabled */ ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Blank _CRS IRQ resource\n")); return AE_OK; } *irq = p->interrupts[0]; break; } case ACPI_RESOURCE_TYPE_EXTENDED_IRQ: { struct acpi_resource_extended_irq *p = &resource->data.extended_irq; if (!p || !p->interrupt_count) { /* * extended IRQ descriptors must * return at least 1 IRQ */ printk(KERN_WARNING PREFIX "Blank _CRS EXT IRQ resource\n"); return AE_OK; } *irq = p->interrupts[0]; break; } break; default: printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n", resource->type); return AE_OK; } return AE_CTRL_TERMINATE; } /* * Run _CRS and set link->irq.active * * return value: * 0 - success * !0 - failure */ static int acpi_pci_link_get_current(struct acpi_pci_link *link) { int result = 0; acpi_status status; int irq = 0; link->irq.active = 0; /* in practice, status disabled is meaningless, ignore it */ if (acpi_strict) { /* Query _STA, set link->device->status */ result = acpi_bus_get_status(link->device); if (result) { printk(KERN_ERR PREFIX "Unable to read status\n"); goto end; } if (!link->device->status.enabled) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n")); return 0; } } /* * Query and parse _CRS to get the current IRQ assignment. */ status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS, acpi_pci_link_check_current, &irq); if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS")); result = -ENODEV; goto end; } if (acpi_strict && !irq) { printk(KERN_ERR PREFIX "_CRS returned 0\n"); result = -ENODEV; } link->irq.active = irq; ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active)); end: return result; } static int acpi_pci_link_set(struct acpi_pci_link *link, int irq) { int result; acpi_status status; struct { struct acpi_resource res; struct acpi_resource end; } *resource; struct acpi_buffer buffer = { 0, NULL }; if (!irq) return -EINVAL; resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL); if (!resource) return -ENOMEM; buffer.length = sizeof(*resource) + 1; buffer.pointer = resource; switch (link->irq.resource_type) { case ACPI_RESOURCE_TYPE_IRQ: resource->res.type = ACPI_RESOURCE_TYPE_IRQ; resource->res.length = sizeof(struct acpi_resource); resource->res.data.irq.triggering = link->irq.triggering; resource->res.data.irq.polarity = link->irq.polarity; if (link->irq.triggering == ACPI_EDGE_SENSITIVE) resource->res.data.irq.sharable = ACPI_EXCLUSIVE; else resource->res.data.irq.sharable = ACPI_SHARED; resource->res.data.irq.interrupt_count = 1; resource->res.data.irq.interrupts[0] = irq; break; case ACPI_RESOURCE_TYPE_EXTENDED_IRQ: resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ; resource->res.length = sizeof(struct acpi_resource); resource->res.data.extended_irq.producer_consumer = ACPI_CONSUMER; resource->res.data.extended_irq.triggering = link->irq.triggering; resource->res.data.extended_irq.polarity = link->irq.polarity; if (link->irq.triggering == ACPI_EDGE_SENSITIVE) resource->res.data.irq.sharable = ACPI_EXCLUSIVE; else resource->res.data.irq.sharable = ACPI_SHARED; resource->res.data.extended_irq.interrupt_count = 1; resource->res.data.extended_irq.interrupts[0] = irq; /* ignore resource_source, it's optional */ break; default: printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type); result = -EINVAL; goto end; } resource->end.type = ACPI_RESOURCE_TYPE_END_TAG; /* Attempt to set the resource */ status = acpi_set_current_resources(link->device->handle, &buffer); /* check for total failure */ if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS")); result = -ENODEV; goto end; } /* Query _STA, set device->status */ result = acpi_bus_get_status(link->device); if (result) { printk(KERN_ERR PREFIX "Unable to read status\n"); goto end; } if (!link->device->status.enabled) { printk(KERN_WARNING PREFIX "%s [%s] disabled and referenced, BIOS bug\n", acpi_device_name(link->device), acpi_device_bid(link->device)); } /* Query _CRS, set link->irq.active */ result = acpi_pci_link_get_current(link); if (result) { goto end; } /* * Is current setting not what we set? * set link->irq.active */ if (link->irq.active != irq) { /* * policy: when _CRS doesn't return what we just _SRS * assume _SRS worked and override _CRS value. */ printk(KERN_WARNING PREFIX "%s [%s] BIOS reported IRQ %d, using IRQ %d\n", acpi_device_name(link->device), acpi_device_bid(link->device), link->irq.active, irq); link->irq.active = irq; } ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active)); end: kfree(resource); return result; } /* -------------------------------------------------------------------------- PCI Link IRQ Management -------------------------------------------------------------------------- */ /* * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt * Link Devices to move the PIRQs around to minimize sharing. * * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs * that the BIOS has already set to active. This is necessary because * ACPI has no automatic means of knowing what ISA IRQs are used. Note that * if the BIOS doesn't set a Link Device active, ACPI needs to program it * even if acpi_irq_nobalance is set. * * A tables of penalties avoids directing PCI interrupts to well known * ISA IRQs. Boot params are available to over-ride the default table: * * List interrupts that are free for PCI use. * acpi_irq_pci=n[,m] * * List interrupts that should not be used for PCI: * acpi_irq_isa=n[,m] * * Note that PCI IRQ routers have a list of possible IRQs, * which may not include the IRQs this table says are available. * * Since this heuristic can't tell the difference between a link * that no device will attach to, vs. a link which may be shared * by multiple active devices -- it is not optimal. * * If interrupt performance is that important, get an IO-APIC system * with a pin dedicated to each device. Or for that matter, an MSI * enabled system. */ #define ACPI_MAX_IRQS 256 #define ACPI_MAX_ISA_IRQ 16 #define PIRQ_PENALTY_PCI_AVAILABLE (0) #define PIRQ_PENALTY_PCI_POSSIBLE (16*16) #define PIRQ_PENALTY_PCI_USING (16*16*16) #define PIRQ_PENALTY_ISA_TYPICAL (16*16*16*16) #define PIRQ_PENALTY_ISA_USED (16*16*16*16*16) #define PIRQ_PENALTY_ISA_ALWAYS (16*16*16*16*16*16) static int acpi_irq_penalty[ACPI_MAX_IRQS] = { PIRQ_PENALTY_ISA_ALWAYS, /* IRQ0 timer */ PIRQ_PENALTY_ISA_ALWAYS, /* IRQ1 keyboard */ PIRQ_PENALTY_ISA_ALWAYS, /* IRQ2 cascade */ PIRQ_PENALTY_ISA_TYPICAL, /* IRQ3 serial */ PIRQ_PENALTY_ISA_TYPICAL, /* IRQ4 serial */ PIRQ_PENALTY_ISA_TYPICAL, /* IRQ5 sometimes SoundBlaster */ PIRQ_PENALTY_ISA_TYPICAL, /* IRQ6 */ PIRQ_PENALTY_ISA_TYPICAL, /* IRQ7 parallel, spurious */ PIRQ_PENALTY_ISA_TYPICAL, /* IRQ8 rtc, sometimes */ PIRQ_PENALTY_PCI_AVAILABLE, /* IRQ9 PCI, often acpi */ PIRQ_PENALTY_PCI_AVAILABLE, /* IRQ10 PCI */ PIRQ_PENALTY_PCI_AVAILABLE, /* IRQ11 PCI */ PIRQ_PENALTY_ISA_USED, /* IRQ12 mouse */ PIRQ_PENALTY_ISA_USED, /* IRQ13 fpe, sometimes */ PIRQ_PENALTY_ISA_USED, /* IRQ14 ide0 */ PIRQ_PENALTY_ISA_USED, /* IRQ15 ide1 */ /* >IRQ15 */ }; int __init acpi_irq_penalty_init(void) { struct acpi_pci_link *link; int i; /* * Update penalties to facilitate IRQ balancing. */ list_for_each_entry(link, &acpi_link_list, list) { /* * reflect the possible and active irqs in the penalty table -- * useful for breaking ties. */ if (link->irq.possible_count) { int penalty = PIRQ_PENALTY_PCI_POSSIBLE / link->irq.possible_count; for (i = 0; i < link->irq.possible_count; i++) { if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ) acpi_irq_penalty[link->irq. possible[i]] += penalty; } } else if (link->irq.active) { acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_POSSIBLE; } } /* Add a penalty for the SCI */ acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING; return 0; } static int acpi_irq_balance = -1; /* 0: static, 1: balance */ static int acpi_pci_link_allocate(struct acpi_pci_link *link) { int irq; int i; if (link->irq.initialized) { if (link->refcnt == 0) /* This means the link is disabled but initialized */ acpi_pci_link_set(link, link->irq.active); return 0; } /* * search for active IRQ in list of possible IRQs. */ for (i = 0; i < link->irq.possible_count; ++i) { if (link->irq.active == link->irq.possible[i]) break; } /* * forget active IRQ that is not in possible list */ if (i == link->irq.possible_count) { if (acpi_strict) printk(KERN_WARNING PREFIX "_CRS %d not found" " in _PRS\n", link->irq.active); link->irq.active = 0; } /* * if active found, use it; else pick entry from end of possible list. */ if (link->irq.active) irq = link->irq.active; else irq = link->irq.possible[link->irq.possible_count - 1]; if (acpi_irq_balance || !link->irq.active) { /* * Select the best IRQ. This is done in reverse to promote * the use of IRQs 9, 10, 11, and >15. */ for (i = (link->irq.possible_count - 1); i >= 0; i--) { if (acpi_irq_penalty[irq] > acpi_irq_penalty[link->irq.possible[i]]) irq = link->irq.possible[i]; } } /* Attempt to enable the link device at this IRQ. */ if (acpi_pci_link_set(link, irq)) { printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. " "Try pci=noacpi or acpi=off\n", acpi_device_name(link->device), acpi_device_bid(link->device)); return -ENODEV; } else { acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING; printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n", acpi_device_name(link->device), acpi_device_bid(link->device), link->irq.active); } link->irq.initialized = 1; return 0; } /* * acpi_pci_link_allocate_irq * success: return IRQ >= 0 * failure: return -1 */ int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering, int *polarity, char **name) { int result; struct acpi_device *device; struct acpi_pci_link *link; result = acpi_bus_get_device(handle, &device); if (result) { printk(KERN_ERR PREFIX "Invalid link device\n"); return -1; } link = acpi_driver_data(device); if (!link) { printk(KERN_ERR PREFIX "Invalid link context\n"); return -1; } /* TBD: Support multiple index (IRQ) entries per Link Device */ if (index) { printk(KERN_ERR PREFIX "Invalid index %d\n", index); return -1; } mutex_lock(&acpi_link_lock); if (acpi_pci_link_allocate(link)) { mutex_unlock(&acpi_link_lock); return -1; } if (!link->irq.active) { mutex_unlock(&acpi_link_lock); printk(KERN_ERR PREFIX "Link active IRQ is 0!\n"); return -1; } link->refcnt++; mutex_unlock(&acpi_link_lock); if (triggering) *triggering = link->irq.triggering; if (polarity) *polarity = link->irq.polarity; if (name) *name = acpi_device_bid(link->device); ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link %s is referenced\n", acpi_device_bid(link->device))); return (link->irq.active); } /* * We don't change link's irq information here. After it is reenabled, we * continue use the info */ int acpi_pci_link_free_irq(acpi_handle handle) { struct acpi_device *device; struct acpi_pci_link *link; acpi_status result; result = acpi_bus_get_device(handle, &device); if (result) { printk(KERN_ERR PREFIX "Invalid link device\n"); return -1; } link = acpi_driver_data(device); if (!link) { printk(KERN_ERR PREFIX "Invalid link context\n"); return -1; } mutex_lock(&acpi_link_lock); if (!link->irq.initialized) { mutex_unlock(&acpi_link_lock); printk(KERN_ERR PREFIX "Link isn't initialized\n"); return -1; } #ifdef FUTURE_USE /* * The Link reference count allows us to _DISable an unused link * and suspend time, and set it again on resume. * However, 2.6.12 still has irq_router.resume * which blindly restores the link state. * So we disable the reference count method * to prevent duplicate acpi_pci_link_set() * which would harm some systems */ link->refcnt--; #endif ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link %s is dereferenced\n", acpi_device_bid(link->device))); if (link->refcnt == 0) acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL); mutex_unlock(&acpi_link_lock); return (link->irq.active); } /* -------------------------------------------------------------------------- Driver Interface -------------------------------------------------------------------------- */ static int acpi_pci_link_add(struct acpi_device *device) { int result; struct acpi_pci_link *link; int i; int found = 0; link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL); if (!link) return -ENOMEM; link->device = device; strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME); strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS); device->driver_data = link; mutex_lock(&acpi_link_lock); result = acpi_pci_link_get_possible(link); if (result) goto end; /* query and set link->irq.active */ acpi_pci_link_get_current(link); printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device), acpi_device_bid(device)); for (i = 0; i < link->irq.possible_count; i++) { if (link->irq.active == link->irq.possible[i]) { printk(" *%d", link->irq.possible[i]); found = 1; } else printk(" %d", link->irq.possible[i]); } printk(")"); if (!found) printk(" *%d", link->irq.active); if (!link->device->status.enabled) printk(", disabled."); printk("\n"); list_add_tail(&link->list, &acpi_link_list); end: /* disable all links -- to be activated on use */ acpi_evaluate_object(device->handle, "_DIS", NULL, NULL); mutex_unlock(&acpi_link_lock); if (result) kfree(link); return result; } static int acpi_pci_link_resume(struct acpi_pci_link *link) { if (link->refcnt && link->irq.active && link->irq.initialized) return (acpi_pci_link_set(link, link->irq.active)); return 0; } static void irqrouter_resume(void) { struct acpi_pci_link *link; list_for_each_entry(link, &acpi_link_list, list) { acpi_pci_link_resume(link); } } static int acpi_pci_link_remove(struct acpi_device *device, int type) { struct acpi_pci_link *link; link = acpi_driver_data(device); mutex_lock(&acpi_link_lock); list_del(&link->list); mutex_unlock(&acpi_link_lock); kfree(link); return 0; } /* * modify acpi_irq_penalty[] from cmdline */ static int __init acpi_irq_penalty_update(char *str, int used) { int i; for (i = 0; i < 16; i++) { int retval; int irq; retval = get_option(&str, &irq); if (!retval) break; /* no number found */ if (irq < 0) continue; if (irq >= ARRAY_SIZE(acpi_irq_penalty)) continue; if (used) acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED; else acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE; if (retval != 2) /* no next number */ break; } return 1; } /* * We'd like PNP to call this routine for the * single ISA_USED value for each legacy device. * But instead it calls us with each POSSIBLE setting. * There is no ISA_POSSIBLE weight, so we simply use * the (small) PCI_USING penalty. */ void acpi_penalize_isa_irq(int irq, int active) { if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) { if (active) acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED; else acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING; } } /* * Over-ride default table to reserve additional IRQs for use by ISA * e.g. acpi_irq_isa=5 * Useful for telling ACPI how not to interfere with your ISA sound card. */ static int __init acpi_irq_isa(char *str) { return acpi_irq_penalty_update(str, 1); } __setup("acpi_irq_isa=", acpi_irq_isa); /* * Over-ride default table to free additional IRQs for use by PCI * e.g. acpi_irq_pci=7,15 * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing. */ static int __init acpi_irq_pci(char *str) { return acpi_irq_penalty_update(str, 0); } __setup("acpi_irq_pci=", acpi_irq_pci); static int __init acpi_irq_nobalance_set(char *str) { acpi_irq_balance = 0; return 1; } __setup("acpi_irq_nobalance", acpi_irq_nobalance_set); static int __init acpi_irq_balance_set(char *str) { acpi_irq_balance = 1; return 1; } __setup("acpi_irq_balance", acpi_irq_balance_set); static struct syscore_ops irqrouter_syscore_ops = { .resume = irqrouter_resume, }; static int __init irqrouter_init_ops(void) { if (!acpi_disabled && !acpi_noirq) register_syscore_ops(&irqrouter_syscore_ops); return 0; } device_initcall(irqrouter_init_ops); static int __init acpi_pci_link_init(void) { if (acpi_noirq) return 0; if (acpi_irq_balance == -1) { /* no command line switch: enable balancing in IOAPIC mode */ if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC) acpi_irq_balance = 1; else acpi_irq_balance = 0; } if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0) return -ENODEV; return 0; } subsys_initcall(acpi_pci_link_init);