From 4a6e68bf96c1fa293717d2f00a68a68c92fa4150 Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Wed, 29 Jun 2016 04:27:35 -0400 Subject: ACPI,PCI,IRQ: factor in PCI possible The change introduced in commit 103544d86976 (ACPI,PCI,IRQ: reduce resource requirements) omitted the initially applied PCI_POSSIBLE penalty when the IRQ is active. Incorrect calculation of the penalty leads the ACPI code to assigning a wrong interrupt number to a PCI INTx interrupt. This would not be as bad as it sounds in theory. It would just cause the interrupts to be shared and result in performance penalty. However, some drivers (like the parallel port driver) don't like interrupt sharing and in the above case they will causes all of the PCI drivers wanting to share the interrupt to be unable to request it. The issue has not been caught in testing because the behavior is platform-specific and depends on the peripherals ending up sharing the IRQ and their drivers. Before the above commit the code would add the PCI_POSSIBLE value divided by the number of possible IRQ users to the IRQ penalty during initialization. Later in that code path, if the IRQ is chosen as the active IRQ or if it is used by ISA; additional penalties are added. Fixes: 103544d86976 (ACPI,PCI,IRQ: reduce resource requirements) Signed-off-by: Sinan Kaya Tested-by: Wim Osterholt [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/pci_link.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) (limited to 'drivers/acpi/pci_link.c') diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c index 4ed4061813e6..db7be62a8222 100644 --- a/drivers/acpi/pci_link.c +++ b/drivers/acpi/pci_link.c @@ -470,6 +470,7 @@ static int acpi_irq_pci_sharing_penalty(int irq) { struct acpi_pci_link *link; int penalty = 0; + int i; list_for_each_entry(link, &acpi_link_list, list) { /* @@ -478,18 +479,14 @@ static int acpi_irq_pci_sharing_penalty(int irq) */ if (link->irq.active && link->irq.active == irq) penalty += PIRQ_PENALTY_PCI_USING; - else { - int i; - - /* - * If a link is inactive, penalize the IRQs it - * might use, but not as severely. - */ - for (i = 0; i < link->irq.possible_count; i++) - if (link->irq.possible[i] == irq) - penalty += PIRQ_PENALTY_PCI_POSSIBLE / - link->irq.possible_count; - } + + /* + * penalize the IRQs PCI might use, but not as severely. + */ + for (i = 0; i < link->irq.possible_count; i++) + if (link->irq.possible[i] == irq) + penalty += PIRQ_PENALTY_PCI_POSSIBLE / + link->irq.possible_count; } return penalty; -- cgit v1.2.3-70-g09d2 From 487cf917ed0d12afaf403d9d77684bf44b8c13be Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Wed, 29 Jun 2016 04:27:36 -0400 Subject: Revert "ACPI, PCI, IRQ: remove redundant code in acpi_irq_penalty_init()" Trying to make the ISA and PCI init functionality common turned out to be a bad idea, because the ISA path depends on external functionality. Restore the previous behavior and limit the refactoring to PCI interrupts only. Fixes: 1fcb6a813c4f "ACPI,PCI,IRQ: remove redundant code in acpi_irq_penalty_init()" Signed-off-by: Sinan Kaya Tested-by: Wim Osterholt Signed-off-by: Rafael J. Wysocki --- arch/x86/pci/acpi.c | 1 + drivers/acpi/pci_link.c | 36 ++++++++++++++++++++++++++++++++++++ include/acpi/acpi_drivers.h | 1 + 3 files changed, 38 insertions(+) (limited to 'drivers/acpi/pci_link.c') diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index b2a4e2a61f6b..3cd69832d7f4 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -396,6 +396,7 @@ int __init pci_acpi_init(void) return -ENODEV; printk(KERN_INFO "PCI: Using ACPI for IRQ routing\n"); + acpi_irq_penalty_init(); pcibios_enable_irq = acpi_pci_irq_enable; pcibios_disable_irq = acpi_pci_irq_disable; x86_init.pci.init_irq = x86_init_noop; diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c index db7be62a8222..606083bb3f00 100644 --- a/drivers/acpi/pci_link.c +++ b/drivers/acpi/pci_link.c @@ -517,6 +517,42 @@ static int acpi_irq_get_penalty(int irq) return penalty; } +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_IRQS) + acpi_isa_irq_penalty[link->irq. + possible[i]] += + penalty; + } + + } else if (link->irq.active && + (link->irq.active < ACPI_MAX_ISA_IRQS)) { + acpi_isa_irq_penalty[link->irq.active] += + PIRQ_PENALTY_PCI_POSSIBLE; + } + } + + return 0; +} + static int acpi_irq_balance = -1; /* 0: static, 1: balance */ static int acpi_pci_link_allocate(struct acpi_pci_link *link) diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h index 797ae2ec8eee..29c691265b49 100644 --- a/include/acpi/acpi_drivers.h +++ b/include/acpi/acpi_drivers.h @@ -78,6 +78,7 @@ /* ACPI PCI Interrupt Link (pci_link.c) */ +int acpi_irq_penalty_init(void); int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering, int *polarity, char **name); int acpi_pci_link_free_irq(acpi_handle handle); -- cgit v1.2.3-70-g09d2 From f7eca374f000bd8bd6aacc2619475fdba0b7ecca Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Wed, 29 Jun 2016 04:27:37 -0400 Subject: ACPI,PCI,IRQ: separate ISA penalty calculation Since commit 103544d86976 (ACPI,PCI,IRQ: reduce resource requirements) the penalty values are calculated on the fly rather than at boot time. This works fine for PCI interrupts but not so well for ISA interrupts. The information on whether or not an ISA interrupt is in use is not available to the pci_link.c code directly. That information is obtained from the outside via acpi_penalize_isa_irq(). [If its "active" argument is true, then the IRQ is in use by ISA.] Since the current code relies on PCI Link objects for determination of penalties, we are factoring in the PCI penalty twice after acpi_penalize_isa_irq() function is called. To avoid that, limit the newly added functionality to just PCI interrupts so that old behavior is still maintained. Fixes: 103544d86976 (ACPI,PCI,IRQ: reduce resource requirements) Signed-off-by: Sinan Kaya Tested-by: Wim Osterholt Signed-off-by: Rafael J. Wysocki --- drivers/acpi/pci_link.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/acpi/pci_link.c') diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c index 606083bb3f00..c983bf733ad3 100644 --- a/drivers/acpi/pci_link.c +++ b/drivers/acpi/pci_link.c @@ -496,9 +496,6 @@ static int acpi_irq_get_penalty(int irq) { int penalty = 0; - if (irq < ACPI_MAX_ISA_IRQS) - penalty += acpi_isa_irq_penalty[irq]; - /* * Penalize IRQ used by ACPI SCI. If ACPI SCI pin attributes conflict * with PCI IRQ attributes, mark ACPI SCI as ISA_ALWAYS so it won't be @@ -513,6 +510,9 @@ static int acpi_irq_get_penalty(int irq) penalty += PIRQ_PENALTY_PCI_USING; } + if (irq < ACPI_MAX_ISA_IRQS) + return penalty + acpi_isa_irq_penalty[irq]; + penalty += acpi_irq_pci_sharing_penalty(irq); return penalty; } -- cgit v1.2.3-70-g09d2