[PATCH V5 0/3] ACPI, PCI, IRQ: revert penalty calculation for ISA and SCI interrupts

[PATCH V5 0/3] ACPI, PCI, IRQ: revert penalty calculation for ISA and SCI interrupts

[Sinan Kaya]

By the time ACPI gets initialized, this code tries to determine an
IRQ number based on penalty values in this array. It will try to locate
the IRQ with the least penalty assignment so that interrupt sharing is
avoided if possible.

A couple of notes about the external APIs:
1. These API can be called before the ACPI is started. Therefore, one
cannot assume that the PCI link objects are initialized for calculating
penalties.
2. The polarity and trigger information passed via the
acpi_penalize_sci_irq from the BIOS may not match what the IRQ subsystem
is reporting as the call might have been placed before the IRQ is
registered by the interrupt subsystem.

The reverted changes were in the direction to remove these external API and
try to calculate the penalties at runtime for the ISA, SCI as well as PCI
IRQS.
This didn't work out well with the existing platforms.

V5:
* clean up the commit message for 1/3 and 2/3
* drop 3/3
* bring back ACPI, PCI IRQ: add PCI_USING penalty for ISA interrupts as 3/3

V4:
https://www.spinics.net/lists/arm-kernel/msg537158.html
* Drop ACPI, PCI IRQ: add PCI_USING penalty for ISA interrupts
* A new patch to isolate early boot ISA penalty calculations from dynamic
penalty calculation by directly modifying the array members in
("ACPI, PCI, IRQ: assign ISA IRQ directly during early boot stages")
* Now that we isolated both SCI and ISA interrupts, revert commit ("Revert
"ACPI,PCI,IRQ: separate ISA penalty calculation"") and commit
("487cf917ed0d
(Revert "ACPI, PCI, IRQ: remove redundant code in acpi_irq_penalty_init()")
to share code between ISA and PCI penalties as originally intended.

V3:
http://www.spinics.net/lists/arm-kernel/msg536208.html
* drop patch #1 as discussed with Bjorn
* add patch #3 to track SCI irq and penalty separately

V2: https://lkml.org/lkml/2016/10/1/106
* Commit message updates

V1:
http://lists-archives.com/linux-kernel/28673954-revert-acpi-pci-irq-reduce-static-irq-array-size-to-16.html
* initial implementation

Sinan Kaya (3):
  ACPI, PCI, IRQ: assign ISA IRQ directly during early boot stages
  ACPI: pci_link: penalize SCI correctly
  ACPI: pci_link: Include PIRQ_PENALTY_PCI_USING for ISA IRQs

 arch/x86/kernel/acpi/boot.c |  1 +
 drivers/acpi/pci_link.c     | 38 +++++++++++++++++++++-----------------
 include/linux/acpi.h        |  1 +
 3 files changed, 23 insertions(+), 17 deletions(-)

-- 
1.9.1

[PATCH V5 1/3] ACPI, PCI, IRQ: assign ISA IRQ directly during early boot stages

[Sinan Kaya]

We do not want to store the SCI penalty in the acpi_isa_irq_penalty[]
table because acpi_isa_irq_penalty[] only holds ISA IRQ penalties and
there's no guarantee that the SCI is an ISA IRQ.  We add in the SCI
penalty as a special case in acpi_irq_get_penalty().

But if we called acpi_penalize_isa_irq() or acpi_irq_penalty_update()
for an SCI that happened to be an ISA IRQ, they stored the SCI
penalty (part of the acpi_irq_get_penalty() return value) in
acpi_isa_irq_penalty[].  Subsequent calls to acpi_irq_get_penalty()
returned a penalty that included *two* SCI penalties.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/acpi/pci_link.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index c983bf7..6229b02 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -849,7 +849,7 @@ static int __init acpi_irq_penalty_update(char *str, int used)
 			continue;
 
 		if (used)
-			new_penalty = acpi_irq_get_penalty(irq) +
+			new_penalty = acpi_isa_irq_penalty[irq] +
 					PIRQ_PENALTY_ISA_USED;
 		else
 			new_penalty = 0;
@@ -871,7 +871,7 @@ static int __init acpi_irq_penalty_update(char *str, int used)
 void acpi_penalize_isa_irq(int irq, int active)
 {
 	if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
-		acpi_isa_irq_penalty[irq] = acpi_irq_get_penalty(irq) +
+		acpi_isa_irq_penalty[irq] +=
 		  (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
 }
 
-- 
1.9.1

[PATCH V5 1/3] ACPI, PCI, IRQ: assign ISA IRQ directly during early boot stages

[Jonathan Liu]

On 24 October 2016 at 15:31, Sinan Kaya <okaya@codeaurora.org> wrote:
> We do not want to store the SCI penalty in the acpi_isa_irq_penalty[]
> table because acpi_isa_irq_penalty[] only holds ISA IRQ penalties and
> there's no guarantee that the SCI is an ISA IRQ.  We add in the SCI
> penalty as a special case in acpi_irq_get_penalty().
>
> But if we called acpi_penalize_isa_irq() or acpi_irq_penalty_update()
> for an SCI that happened to be an ISA IRQ, they stored the SCI
> penalty (part of the acpi_irq_get_penalty() return value) in
> acpi_isa_irq_penalty[].  Subsequent calls to acpi_irq_get_penalty()
> returned a penalty that included *two* SCI penalties.
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
>  drivers/acpi/pci_link.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
> index c983bf7..6229b02 100644
> --- a/drivers/acpi/pci_link.c
> +++ b/drivers/acpi/pci_link.c
> @@ -849,7 +849,7 @@ static int __init acpi_irq_penalty_update(char *str, int used)
>                         continue;
>
>                 if (used)
> -                       new_penalty = acpi_irq_get_penalty(irq) +
> +                       new_penalty = acpi_isa_irq_penalty[irq] +
>                                         PIRQ_PENALTY_ISA_USED;
>                 else
>                         new_penalty = 0;
> @@ -871,7 +871,7 @@ static int __init acpi_irq_penalty_update(char *str, int used)
>  void acpi_penalize_isa_irq(int irq, int active)
>  {
>         if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
> -               acpi_isa_irq_penalty[irq] = acpi_irq_get_penalty(irq) +
> +               acpi_isa_irq_penalty[irq] +=
>                   (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
>  }
>
> --
> 1.9.1
>

This series fixes one or more network adapters not working in Linux
32-bit x86 guest running inside VirtualBox if I have 4 network
adapters enabled.
The following message no longer appears in the kernel log:
ACPI: No IRQ available for PCI Interrupt Link [LNKD]. Try pci=noacpi or acpi=off

Tested-by: Jonathan Liu <net147@gmail.com>

[PATCH V5 2/3] ACPI: pci_link: penalize SCI correctly

[Sinan Kaya]

Ondrej reported that IRQs stopped working in v4.7 on several
platforms.  A typical scenario, from Ondrej's VT82C694X/694X, is:

ACPI: Using PIC for interrupt routing
ACPI: PCI Interrupt Link [LNKA] (IRQs 1 3 4 5 6 7 10 *11 12 14 15)
ACPI: No IRQ available for PCI Interrupt Link [LNKA]
8139too 0000:00:0f.0: PCI INT A: no GSI

We're using PIC routing, so acpi_irq_balance == 0, and LNKA is already
active at IRQ 11. In that case, acpi_pci_link_allocate() only tries
to use the active IRQ (IRQ 11) which also happens to be the SCI.

We should penalize the SCI by PIRQ_PENALTY_PCI_USING, but
irq_get_trigger_type(11) returns something other than
IRQ_TYPE_LEVEL_LOW, so we penalize it by PIRQ_PENALTY_ISA_ALWAYS
instead, which makes acpi_pci_link_allocate() assume the IRQ isn't
available and give up.

Add acpi_penalize_sci_irq() so platforms can tell us the SCI IRQ,
trigger, and polarity directly and we don't have to depend on
irq_get_trigger_type().

Link: http://lkml.kernel.org/r/201609251512.05657.linux at rainbow-software.org
Reported-by: Ondrej Zary <linux@rainbow-software.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 arch/x86/kernel/acpi/boot.c |  1 +
 drivers/acpi/pci_link.c     | 30 +++++++++++++++---------------
 include/linux/acpi.h        |  1 +
 3 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 90d84c3..0ffd26e 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -453,6 +453,7 @@ static void __init acpi_sci_ioapic_setup(u8 bus_irq, u16 polarity, u16 trigger,
 		polarity = acpi_sci_flags & ACPI_MADT_POLARITY_MASK;
 
 	mp_override_legacy_irq(bus_irq, polarity, trigger, gsi);
+	acpi_penalize_sci_irq(bus_irq, trigger, polarity);
 
 	/*
 	 * stash over-ride to indicate we've been here
diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index 6229b02..74bf96e 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -87,6 +87,7 @@ struct acpi_pci_link {
 
 static LIST_HEAD(acpi_link_list);
 static DEFINE_MUTEX(acpi_link_lock);
+static int sci_irq = -1, sci_penalty;
 
 /* --------------------------------------------------------------------------
                             PCI Link Device Management
@@ -496,25 +497,13 @@ static int acpi_irq_get_penalty(int irq)
 {
 	int penalty = 0;
 
-	/*
-	* 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
-	* use for PCI IRQs.
-	*/
-	if (irq == acpi_gbl_FADT.sci_interrupt) {
-		u32 type = irq_get_trigger_type(irq) & IRQ_TYPE_SENSE_MASK;
-
-		if (type != IRQ_TYPE_LEVEL_LOW)
-			penalty += PIRQ_PENALTY_ISA_ALWAYS;
-		else
-			penalty += PIRQ_PENALTY_PCI_USING;
-	}
+	if (irq == sci_irq)
+		penalty += sci_penalty;
 
 	if (irq < ACPI_MAX_ISA_IRQS)
 		return penalty + acpi_isa_irq_penalty[irq];
 
-	penalty += acpi_irq_pci_sharing_penalty(irq);
-	return penalty;
+	return penalty + acpi_irq_pci_sharing_penalty(irq);
 }
 
 int __init acpi_irq_penalty_init(void)
@@ -881,6 +870,17 @@ bool acpi_isa_irq_available(int irq)
 		    acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
 }
 
+void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
+{
+	sci_irq = irq;
+
+	if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
+	    polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
+		sci_penalty = PIRQ_PENALTY_PCI_USING;
+	else
+		sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
+}
+
 /*
  * Over-ride default table to reserve additional IRQs for use by ISA
  * e.g. acpi_irq_isa=5
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index c5eaf2f..67d1d3e 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -318,6 +318,7 @@ struct pci_dev;
 int acpi_pci_irq_enable (struct pci_dev *dev);
 void acpi_penalize_isa_irq(int irq, int active);
 bool acpi_isa_irq_available(int irq);
+void acpi_penalize_sci_irq(int irq, int trigger, int polarity);
 void acpi_pci_irq_disable (struct pci_dev *dev);
 
 extern int ec_read(u8 addr, u8 *val);
-- 
1.9.1

[PATCH V5 2/3] ACPI: pci_link: penalize SCI correctly

[Jonathan Liu]

On 24 October 2016 at 15:31, Sinan Kaya <okaya@codeaurora.org> wrote:
> Ondrej reported that IRQs stopped working in v4.7 on several
> platforms.  A typical scenario, from Ondrej's VT82C694X/694X, is:
>
> ACPI: Using PIC for interrupt routing
> ACPI: PCI Interrupt Link [LNKA] (IRQs 1 3 4 5 6 7 10 *11 12 14 15)
> ACPI: No IRQ available for PCI Interrupt Link [LNKA]
> 8139too 0000:00:0f.0: PCI INT A: no GSI
>
> We're using PIC routing, so acpi_irq_balance == 0, and LNKA is already
> active at IRQ 11. In that case, acpi_pci_link_allocate() only tries
> to use the active IRQ (IRQ 11) which also happens to be the SCI.
>
> We should penalize the SCI by PIRQ_PENALTY_PCI_USING, but
> irq_get_trigger_type(11) returns something other than
> IRQ_TYPE_LEVEL_LOW, so we penalize it by PIRQ_PENALTY_ISA_ALWAYS
> instead, which makes acpi_pci_link_allocate() assume the IRQ isn't
> available and give up.
>
> Add acpi_penalize_sci_irq() so platforms can tell us the SCI IRQ,
> trigger, and polarity directly and we don't have to depend on
> irq_get_trigger_type().
>
> Link: http://lkml.kernel.org/r/201609251512.05657.linux at rainbow-software.org
> Reported-by: Ondrej Zary <linux@rainbow-software.org>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>  arch/x86/kernel/acpi/boot.c |  1 +
>  drivers/acpi/pci_link.c     | 30 +++++++++++++++---------------
>  include/linux/acpi.h        |  1 +
>  3 files changed, 17 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
> index 90d84c3..0ffd26e 100644
> --- a/arch/x86/kernel/acpi/boot.c
> +++ b/arch/x86/kernel/acpi/boot.c
> @@ -453,6 +453,7 @@ static void __init acpi_sci_ioapic_setup(u8 bus_irq, u16 polarity, u16 trigger,
>                 polarity = acpi_sci_flags & ACPI_MADT_POLARITY_MASK;
>
>         mp_override_legacy_irq(bus_irq, polarity, trigger, gsi);
> +       acpi_penalize_sci_irq(bus_irq, trigger, polarity);
>
>         /*
>          * stash over-ride to indicate we've been here
> diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
> index 6229b02..74bf96e 100644
> --- a/drivers/acpi/pci_link.c
> +++ b/drivers/acpi/pci_link.c
> @@ -87,6 +87,7 @@ struct acpi_pci_link {
>
>  static LIST_HEAD(acpi_link_list);
>  static DEFINE_MUTEX(acpi_link_lock);
> +static int sci_irq = -1, sci_penalty;
>
>  /* --------------------------------------------------------------------------
>                              PCI Link Device Management
> @@ -496,25 +497,13 @@ static int acpi_irq_get_penalty(int irq)
>  {
>         int penalty = 0;
>
> -       /*
> -       * 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
> -       * use for PCI IRQs.
> -       */
> -       if (irq == acpi_gbl_FADT.sci_interrupt) {
> -               u32 type = irq_get_trigger_type(irq) & IRQ_TYPE_SENSE_MASK;
> -
> -               if (type != IRQ_TYPE_LEVEL_LOW)
> -                       penalty += PIRQ_PENALTY_ISA_ALWAYS;
> -               else
> -                       penalty += PIRQ_PENALTY_PCI_USING;
> -       }
> +       if (irq == sci_irq)
> +               penalty += sci_penalty;
>
>         if (irq < ACPI_MAX_ISA_IRQS)
>                 return penalty + acpi_isa_irq_penalty[irq];
>
> -       penalty += acpi_irq_pci_sharing_penalty(irq);
> -       return penalty;
> +       return penalty + acpi_irq_pci_sharing_penalty(irq);
>  }
>
>  int __init acpi_irq_penalty_init(void)
> @@ -881,6 +870,17 @@ bool acpi_isa_irq_available(int irq)
>                     acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
>  }
>
> +void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
> +{
> +       sci_irq = irq;
> +
> +       if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
> +           polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
> +               sci_penalty = PIRQ_PENALTY_PCI_USING;
> +       else
> +               sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
> +}
> +
>  /*
>   * Over-ride default table to reserve additional IRQs for use by ISA
>   * e.g. acpi_irq_isa=5
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index c5eaf2f..67d1d3e 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -318,6 +318,7 @@ struct pci_dev;
>  int acpi_pci_irq_enable (struct pci_dev *dev);
>  void acpi_penalize_isa_irq(int irq, int active);
>  bool acpi_isa_irq_available(int irq);
> +void acpi_penalize_sci_irq(int irq, int trigger, int polarity);
>  void acpi_pci_irq_disable (struct pci_dev *dev);
>
>  extern int ec_read(u8 addr, u8 *val);
> --
> 1.9.1
>

This series fixes one or more network adapters not working in Linux
32-bit x86 guest running inside VirtualBox if I have 4 network
adapters enabled.
The following message no longer appears in the kernel log:
ACPI: No IRQ available for PCI Interrupt Link [LNKD]. Try pci=noacpi or acpi=off

Tested-by: Jonathan Liu <net147@gmail.com>

[PATCH V5 3/3] ACPI: pci_link: Include PIRQ_PENALTY_PCI_USING for ISA IRQs

[Sinan Kaya]

Commit 103544d86976 ("ACPI,PCI,IRQ: reduce resource requirements")
replaced the addition of PIRQ_PENALTY_PCI_USING in acpi_pci_link_allocate()
with an addition in acpi_irq_pci_sharing_penalty(), but f7eca374f000
("ACPI,PCI,IRQ: separate ISA penalty calculation") removed the use
of acpi_irq_pci_sharing_penalty() for ISA IRQs.

Therefore, PIRQ_PENALTY_PCI_USING is missing from ISA IRQs used by
interrupt links.  Include that penalty by adding it in the
acpi_pci_link_allocate() path.

Fixes: f7eca374f000 ("ACPI,PCI,IRQ: separate ISA penalty calculation")
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/acpi/pci_link.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index 74bf96e..bc3d914 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -608,6 +608,10 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 			    acpi_device_bid(link->device));
 		return -ENODEV;
 	} else {
+		if (link->irq.active < ACPI_MAX_ISA_IRQS)
+			acpi_isa_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);
-- 
1.9.1

[PATCH V5 3/3] ACPI: pci_link: Include PIRQ_PENALTY_PCI_USING for ISA IRQs

[Jonathan Liu]

On 24 October 2016 at 15:31, Sinan Kaya <okaya@codeaurora.org> wrote:
> Commit 103544d86976 ("ACPI,PCI,IRQ: reduce resource requirements")
> replaced the addition of PIRQ_PENALTY_PCI_USING in acpi_pci_link_allocate()
> with an addition in acpi_irq_pci_sharing_penalty(), but f7eca374f000
> ("ACPI,PCI,IRQ: separate ISA penalty calculation") removed the use
> of acpi_irq_pci_sharing_penalty() for ISA IRQs.
>
> Therefore, PIRQ_PENALTY_PCI_USING is missing from ISA IRQs used by
> interrupt links.  Include that penalty by adding it in the
> acpi_pci_link_allocate() path.
>
> Fixes: f7eca374f000 ("ACPI,PCI,IRQ: separate ISA penalty calculation")
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
>  drivers/acpi/pci_link.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
> index 74bf96e..bc3d914 100644
> --- a/drivers/acpi/pci_link.c
> +++ b/drivers/acpi/pci_link.c
> @@ -608,6 +608,10 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
>                             acpi_device_bid(link->device));
>                 return -ENODEV;
>         } else {
> +               if (link->irq.active < ACPI_MAX_ISA_IRQS)
> +                       acpi_isa_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);
> --
> 1.9.1
>

This series fixes one or more network adapters not working in Linux
32-bit x86 guest running inside VirtualBox if I have 4 network
adapters enabled.
The following message no longer appears in the kernel log:
ACPI: No IRQ available for PCI Interrupt Link [LNKD]. Try pci=noacpi or acpi=off

Tested-by: Jonathan Liu <net147@gmail.com>

[PATCH V5 3/3] ACPI: pci_link: Include PIRQ_PENALTY_PCI_USING for ISA IRQs

[Sinan Kaya]

Thanks Jonathan,

On 10/24/2016 12:46 AM, Jonathan Liu wrote:
>> 1.9.1
>> >
> This series fixes one or more network adapters not working in Linux
> 32-bit x86 guest running inside VirtualBox if I have 4 network
> adapters enabled.
> The following message no longer appears in the kernel log:
> ACPI: No IRQ available for PCI Interrupt Link [LNKD]. Try pci=noacpi or acpi=off
> 
> Tested-by: Jonathan Liu <net147@gmail.com>

Can we also get some more testing coverage from the people in TO?

We want to make sure that we fixed all outstanding ACPI PCI IRQ issues.

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH V5 0/3] ACPI,PCI,IRQ: revert penalty calculation for ISA and SCI interrupts

[Rafael J. Wysocki]

On Mon, Oct 24, 2016 at 6:31 AM, Sinan Kaya <okaya@codeaurora.org> wrote:
>
> By the time ACPI gets initialized, this code tries to determine an
> IRQ number based on penalty values in this array. It will try to locate
> the IRQ with the least penalty assignment so that interrupt sharing is
> avoided if possible.
>
> A couple of notes about the external APIs:
> 1. These API can be called before the ACPI is started. Therefore, one
> cannot assume that the PCI link objects are initialized for calculating
> penalties.
> 2. The polarity and trigger information passed via the
> acpi_penalize_sci_irq from the BIOS may not match what the IRQ subsystem
> is reporting as the call might have been placed before the IRQ is
> registered by the interrupt subsystem.
>
> The reverted changes were in the direction to remove these external API and
> try to calculate the penalties at runtime for the ISA, SCI as well as PCI
> IRQS.
> This didn't work out well with the existing platforms.
>
> V5:
> * clean up the commit message for 1/3 and 2/3
> * drop 3/3
> * bring back ACPI, PCI IRQ: add PCI_USING penalty for ISA interrupts as 3/3
>
> V4:
> https://www.spinics.net/lists/arm-kernel/msg537158.html
> * Drop ACPI, PCI IRQ: add PCI_USING penalty for ISA interrupts
> * A new patch to isolate early boot ISA penalty calculations from dynamic
> penalty calculation by directly modifying the array members in
> ("ACPI, PCI, IRQ: assign ISA IRQ directly during early boot stages")
> * Now that we isolated both SCI and ISA interrupts, revert commit ("Revert
> "ACPI,PCI,IRQ: separate ISA penalty calculation"") and commit
> ("487cf917ed0d
> (Revert "ACPI, PCI, IRQ: remove redundant code in acpi_irq_penalty_init()")
> to share code between ISA and PCI penalties as originally intended.
>
> V3:
> http://www.spinics.net/lists/arm-kernel/msg536208.html
> * drop patch #1 as discussed with Bjorn
> * add patch #3 to track SCI irq and penalty separately
>
> V2: https://lkml.org/lkml/2016/10/1/106
> * Commit message updates
>
> V1:
> http://lists-archives.com/linux-kernel/28673954-revert-acpi-pci-irq-reduce-static-irq-array-size-to-16.html
> * initial implementation
>
> Sinan Kaya (3):
>   ACPI, PCI, IRQ: assign ISA IRQ directly during early boot stages
>   ACPI: pci_link: penalize SCI correctly
>   ACPI: pci_link: Include PIRQ_PENALTY_PCI_USING for ISA IRQs
>
>  arch/x86/kernel/acpi/boot.c |  1 +
>  drivers/acpi/pci_link.c     | 38 +++++++++++++++++++++-----------------
>  include/linux/acpi.h        |  1 +
>  3 files changed, 23 insertions(+), 17 deletions(-)

I've queued up this series for the next ACPI pull request with 4.9 fixes.

Thanks,
Rafael