* [PATCH] acpi/pci_link.c
@ 2003-11-05 4:50 Len Brown
0 siblings, 0 replies; only message in thread
From: Len Brown @ 2003-11-05 4:50 UTC (permalink / raw)
To: ACPI Developers; +Cc: linux-acpi
[-- Attachment #1: Type: text/plain, Size: 1364 bytes --]
Please review this interrupt patch.
It applies to both 2.4 and 2.6.
thanks,
-Len
What the patch does:
Re-enables PCI Link Device programming by default.
This fixes systems that stopped working when we
stopped re-programming active PIRQs:
http://bugzilla.kernel.org/show_bug.cgi?id=1440
For systems that mark their PIRQ links active,
this allows the kernel to again distribute
PIRQs across all available IRQs:
http://bugzilla.kernel.org/show_bug.cgi?id=1391
Fixes an off-by-one bug in the PIRQ distribution
code that caused one of the possible IRQs to be
ignored on every PIRQ link.
To aid in minimizing IRQ sharing, added cmdline
"acpi_irq_pci=" to tell the kernel when it can
use an IRQ for PCI, even if the kernel default
is to reserve that IRQ for ISA use.
Conversely, added "acpi_irq_isa=" cmdline param
to reserve IRQs for ISA.
Workaround for SoundBlaster vs. ACPI PIRQ routing issues:
http://bugzilla.kernel.org/show_bug.cgi?id=430
http://bugzilla.kernel.org/show_bug.cgi?id=1139
Previously we had disabled re-programming active PIRQs to
address http://bugzilla.kernel.org/show_bug.cgi?id=1186
This change will break those broken systems again, unless
they've been fixed in other ways.
Mitigated the impact with a new cmdline parameter
"acpi_irq_static" that restores the previous behavior
of not moving PCI Link devices that are marked active.
[-- Attachment #2: pci_link.patch --]
[-- Type: text/plain, Size: 7820 bytes --]
===== drivers/acpi/pci_link.c 1.20 vs edited =====
--- 1.20/drivers/acpi/pci_link.c Tue Sep 30 00:50:34 2003
+++ edited/drivers/acpi/pci_link.c Tue Nov 4 23:40:44 2003
@@ -99,7 +99,7 @@
void *context)
{
struct acpi_pci_link *link = (struct acpi_pci_link *) context;
- int i = 0;
+ u32 i = 0;
ACPI_FUNCTION_TRACE("acpi_pci_link_check_possible");
@@ -294,7 +294,10 @@
if (!link->irq.active) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "No active IRQ resource found\n"));
- printk(KERN_WARNING "_CRS returns NULL! Using IRQ %d for device (%s [%s]).\n", irq, acpi_device_name(link->device), acpi_device_bid(link->device));
+ printk(KERN_WARNING "_CRS returns NULL! Using IRQ %d for"
+ "device (%s [%s]).\n", irq,
+ acpi_device_name(link->device),
+ acpi_device_bid(link->device));
link->irq.active = irq;
}
@@ -429,30 +432,61 @@
PCI Link IRQ Management
-------------------------------------------------------------------------- */
-#define ACPI_MAX_IRQS 256
-#define ACPI_MAX_ISA_IRQ 16
-
/*
- * IRQ penalties are used to promote PCI IRQ balancing. We set each ISA-
- * possible IRQ (0-15) with a default penalty relative to its feasibility
- * for PCI's use:
+ * Interrupt sharing can impact performance, so this code
+ * spreads the PCI link devices across the available IRQs.
+ *
+ * A tables of penalties avoids directing PCI interrupts to well known
+ * ISA IRQs. Boot params are available to over-ride the default table:
*
- * Never use: 0, 1, 2 (timer, keyboard, and cascade)
- * Avoid using: 13, 14, and 15 (FP error and IDE)
- * Penalize: 3, 4, 6, 7, 12 (known ISA uses)
+ * List interrupts that are free for PCI use.
+ * acpi_irq_pci=n[,m]
*
- * Thus we're left with IRQs 5, 9, 10, 11, and everything above 15 (IO[S]APIC)
- * as 'best bets' for PCI use.
+ * 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] = {
- 1000000, 1000000, 1000000, 10000,
- 10000, 0, 10000, 10000,
- 10000, 0, 0, 0,
- 10000, 100000, 100000, 100000,
+ 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_PCI_AVAILABLE, /* IRQ5 PCI */
+ 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_TYPICAL, /* IRQ12 mouse */
+ PIRQ_PENALTY_ISA_USED, /* IRQ13 fpe, sometimes */
+ PIRQ_PENALTY_ISA_USED, /* IRQ14 ide0 */
+ PIRQ_PENALTY_ISA_USED, /* IRQ15 ide1 */
+ /* >IRQ15 */
};
-
int
acpi_pci_link_check (void)
{
@@ -473,20 +507,27 @@
continue;
}
- if (link->irq.active)
- acpi_irq_penalty[link->irq.active] += 100;
- else if (link->irq.possible_count) {
- int penalty = 100 / link->irq.possible_count;
- for (i=0; i<link->irq.possible_count; i++) {
+ /*
+ * 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;
}
}
-
return_VALUE(0);
}
+static int acpi_irq_static; /* don't re-program active IRQs */
+
static int acpi_pci_link_allocate(struct acpi_pci_link* link) {
int irq;
int i;
@@ -500,12 +541,14 @@
irq = link->irq.active;
} else {
irq = link->irq.possible[0];
+ }
+ if (!(link->irq.active && acpi_irq_static)) {
/*
* 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--) {
+ 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];
}
@@ -518,13 +561,14 @@
acpi_device_bid(link->device));
return_VALUE(-ENODEV);
} else {
- acpi_irq_penalty[link->irq.active] += 100;
+ acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
printk(PREFIX "%s [%s] enabled at IRQ %d\n",
acpi_device_name(link->device),
acpi_device_bid(link->device), link->irq.active);
}
link->irq.setonboot = 1;
+
return_VALUE(0);
}
@@ -607,9 +651,12 @@
if (result)
goto end;
+ /* query and set link->irq.active */
acpi_pci_link_get_current(link);
- printk(PREFIX "%s [%s] (IRQs", acpi_device_name(device), acpi_device_bid(device));
+//#ifdef CONFIG_ACPI_DEBUG
+ printk(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]);
@@ -619,6 +666,7 @@
printk(" %d", link->irq.possible[i]);
}
printk(")\n");
+//#endif /* CONFIG_ACPI_DEBUG */
/* TBD: Acquire/release lock */
list_add_tail(&link->node, &acpi_link.entries);
@@ -670,5 +718,73 @@
return_VALUE(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 >= ACPI_MAX_IRQS)
+ 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;
+}
+
+/*
+ * 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
+ * Useful for freeing 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);
+
+/*
+ * Do not re-program active IRQs,
+ * keep the static active settings left by the BIOS.
+ * Useful for working around broken BIOS.
+ */
+static int __init acpi_irq_static_set(char *str)
+{
+ acpi_irq_static = 1;
+ return(1);
+}
+__setup("acpi_irq_static", acpi_irq_static_set);
subsys_initcall(acpi_pci_link_init);
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2003-11-05 4:50 [PATCH] acpi/pci_link.c Len Brown
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