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SubjectRe: Switch APIC to driver model (and make S3 sleep with APIC on)
Hi!

> >> - You're hardcoding that the local-APIC NMI watchdog is the
> >> only possible sub-client of the local APIC. Not true.
> >> - perfctr_pmdev exists precisely to handle both these cases
> >> in a clean way.
> >
> >While being as ugly as night, which is even noted in sources:
> >
> >- /* 'perfctr_pmdev' is here because the current (2.4.1) PM
> >- callback system doesn't handle hierarchical dependencies */
> >
> >Nothing prevents more clients from registering as subtrees to APIC. I
> >did not do that for NMI watchdog because it is hardcoded in Makefile,
> >anyway.
>
> Not "more" clients, OTHER clients. They're exclusive.
> The NMI watchdog simply happens to be the default client, but it
> needs to unregister itself before any other client can take over
> the performance counters and the local APIC's LVTPC entry.
> (And that's what happens today.)

How can this be? I see nmi.c being unconditionaly compiled-in. Where
are the other clients you are talking about?

> If the device model handles hierarchical dependencies correctly,
> there should be no need to hardcode calls from the local APIC's
> PM routines to whoever happens to be its current sub-client.
>
> (And if it doesn't do this correctly, please fix the device
> model first before migrating apic.c/nmi.c to it.)
>
> >I'll fix APM to call device model methods.
>
> Good.
>
> >Because PM_SUSPEND/PM_RESUME is ugly and can not be made to work
> >(devices are hierarchical, and PM_SUSPEND/PM_RESUME system does not
> >honour that).
>
> Agreed, but existing PM users do work. Most are leaves in the
> dependency tree (e.g. sound cards). The only one I know of that
> isn't is apic.c, and it has a local workaround as you noted.
>
> Given that we're supposed to be in a feature freeze getting 2.5
> into some kind of 2.6-worthy shape soonish, I think PM should
> be hooked into the device model as a legacy API.

Well, PM will be left there for APM. I don't want to call it from
swsusp...

Do you think you could try this patch to see if it works for you? [It
should address everything except "modular nmi", where I am not
convinced it is needed.]

Pavel

--- clean/arch/i386/kernel/apic.c 2003-01-05 22:58:18.000000000 +0100
+++ linux-swsusp/arch/i386/kernel/apic.c 2003-01-28 10:28:05.000000000 +0100
@@ -23,6 +23,7 @@
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/kernel_stat.h>
+#include <linux/delay.h>

#include <asm/atomic.h>
#include <asm/smp.h>
@@ -54,6 +55,8 @@
int prof_old_multiplier[NR_CPUS] = { 1, };
int prof_counter[NR_CPUS] = { 1, };

+unsigned long apic_phys;
+
int get_maxlvt(void)
{
unsigned int v, ver, maxlvt;
@@ -438,8 +441,8 @@
}

#ifdef CONFIG_PM
-
#include <linux/slab.h>
+#include <linux/device.h>
#include <linux/pm.h>

static struct {
@@ -447,9 +450,6 @@
not the BIOS; this signifies that we are also responsible
for disabling it before entering apm/acpi suspend */
int active;
- /* 'perfctr_pmdev' is here because the current (2.4.1) PM
- callback system doesn't handle hierarchical dependencies */
- struct pm_dev *perfctr_pmdev;
/* r/w apic fields */
unsigned int apic_id;
unsigned int apic_taskpri;
@@ -466,13 +466,15 @@
unsigned int apic_thmr;
} apic_pm_state;

-static void apic_pm_suspend(void *data)
+static int apic_suspend(struct device *dev, u32 state, u32 level)
{
unsigned int l, h;
unsigned long flags;

- if (apic_pm_state.perfctr_pmdev)
- pm_send(apic_pm_state.perfctr_pmdev, PM_SUSPEND, data);
+ if (level != SUSPEND_DISABLE)
+ return 0;
+
+ disable_apic_nmi_watchdog();
apic_pm_state.apic_id = apic_read(APIC_ID);
apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
apic_pm_state.apic_ldr = apic_read(APIC_LDR);
@@ -493,13 +495,19 @@
l &= ~MSR_IA32_APICBASE_ENABLE;
wrmsr(MSR_IA32_APICBASE, l, h);
local_irq_restore(flags);
+ return 0;
}

-static void apic_pm_resume(void *data)
+static int apic_resume(struct device *dev, u32 level)
{
unsigned int l, h;
unsigned long flags;

+ if (level != RESUME_POWER_ON)
+ return 0;
+
+ set_fixmap_nocache(FIX_APIC_BASE, apic_phys); /* FIXME: this is needed for S3 resume, but why? */
+
local_irq_save(flags);
rdmsr(MSR_IA32_APICBASE, l, h);
l &= ~MSR_IA32_APICBASE_BASE;
@@ -524,74 +532,35 @@
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
local_irq_restore(flags);
- if (apic_pm_state.perfctr_pmdev)
- pm_send(apic_pm_state.perfctr_pmdev, PM_RESUME, data);
-}
-
-static int apic_pm_callback(struct pm_dev *dev, pm_request_t rqst, void *data)
-{
- switch (rqst) {
- case PM_SUSPEND:
- apic_pm_suspend(data);
- break;
- case PM_RESUME:
- apic_pm_resume(data);
- break;
- }
+ setup_apic_nmi_watchdog();
return 0;
}

-/* perfctr driver should call this instead of pm_register() */
-struct pm_dev *apic_pm_register(pm_dev_t type,
- unsigned long id,
- pm_callback callback)
-{
- struct pm_dev *dev;
-
- if (!apic_pm_state.active)
- return pm_register(type, id, callback);
- if (apic_pm_state.perfctr_pmdev)
- return NULL; /* we're busy */
- dev = kmalloc(sizeof(struct pm_dev), GFP_KERNEL);
- if (dev) {
- memset(dev, 0, sizeof(*dev));
- dev->type = type;
- dev->id = id;
- dev->callback = callback;
- apic_pm_state.perfctr_pmdev = dev;
- }
- return dev;
-}
-
-/* perfctr driver should call this instead of pm_unregister() */
-void apic_pm_unregister(struct pm_dev *dev)
-{
- if (!apic_pm_state.active) {
- pm_unregister(dev);
- } else if (dev == apic_pm_state.perfctr_pmdev) {
- apic_pm_state.perfctr_pmdev = NULL;
- kfree(dev);
- }
-}
-
-static void __init apic_pm_init1(void)
-{
- /* can't pm_register() at this early stage in the boot process
- (causes an immediate reboot), so just set the flag */
- apic_pm_state.active = 1;
-}
+static struct device_driver apic_driver = {
+ .name = "apic",
+ .bus = &system_bus_type,
+ .resume = apic_resume,
+ .suspend = apic_suspend,
+};
+
+static struct sys_device device_apic = {
+ .name = "apic",
+ .id = 0,
+ .dev = {
+ .name = "APIC",
+ .driver = &apic_driver,
+ },
+};

-static void __init apic_pm_init2(void)
+static int __init init_apic_devicefs(void)
{
+ driver_register(&apic_driver);
if (apic_pm_state.active)
- pm_register(PM_SYS_DEV, 0, apic_pm_callback);
+ return sys_device_register(&device_apic);
+ return 0;
}

-#else /* CONFIG_PM */
-
-static inline void apic_pm_init1(void) { }
-static inline void apic_pm_init2(void) { }
-
+device_initcall(init_apic_devicefs);
#endif /* CONFIG_PM */

/*
@@ -658,9 +627,6 @@
nmi_watchdog = NMI_LOCAL_APIC;

printk("Found and enabled local APIC!\n");
-
- apic_pm_init1();
-
return 0;

no_apic:
@@ -670,8 +636,6 @@

void __init init_apic_mappings(void)
{
- unsigned long apic_phys;
-
/*
* If no local APIC can be found then set up a fake all
* zeroes page to simulate the local APIC and another
@@ -1141,8 +1105,6 @@
phys_cpu_present_map = 1;
apic_write_around(APIC_ID, boot_cpu_physical_apicid);

- apic_pm_init2();
-
setup_local_APIC();

if (nmi_watchdog == NMI_LOCAL_APIC)
--- clean/arch/i386/kernel/apm.c 2003-01-09 22:16:11.000000000 +0100
+++ linux-swsusp/arch/i386/kernel/apm.c 2003-01-28 10:35:51.000000000 +0100
@@ -1263,6 +1263,11 @@
}
printk(KERN_CRIT "apm: suspend was vetoed, but suspending anyway.\n");
}
+
+ device_suspend(3, SUSPEND_NOTIFY);
+ device_suspend(3, SUSPEND_SAVE_STATE);
+ device_suspend(3, SUSPEND_DISABLE);
+
/* serialize with the timer interrupt */
write_lock_irq(&xtime_lock);

@@ -1283,6 +1288,8 @@
if (err != APM_SUCCESS)
apm_error("suspend", err);
err = (err == APM_SUCCESS) ? 0 : -EIO;
+ device_resume(RESUME_RESTORE_STATE);
+ device_resume(RESUME_ENABLE);
pm_send_all(PM_RESUME, (void *)0);
queue_event(APM_NORMAL_RESUME, NULL);
out:
@@ -1396,6 +1403,8 @@
write_lock_irq(&xtime_lock);
set_time();
write_unlock_irq(&xtime_lock);
+ device_resume(RESUME_RESTORE_STATE);
+ device_resume(RESUME_ENABLE);
pm_send_all(PM_RESUME, (void *)0);
queue_event(event, NULL);
}
--- clean/arch/i386/kernel/i386_ksyms.c 2003-01-17 23:09:51.000000000 +0100
+++ linux-swsusp/arch/i386/kernel/i386_ksyms.c 2003-01-19 19:58:34.000000000 +0100
@@ -161,10 +161,6 @@
EXPORT_SYMBOL(flush_tlb_page);
#endif

-#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PM)
-EXPORT_SYMBOL_GPL(set_nmi_pm_callback);
-EXPORT_SYMBOL_GPL(unset_nmi_pm_callback);
-#endif
#ifdef CONFIG_X86_IO_APIC
EXPORT_SYMBOL(IO_APIC_get_PCI_irq_vector);
#endif
--- clean/arch/i386/kernel/nmi.c 2003-01-05 22:58:19.000000000 +0100
+++ linux-swsusp/arch/i386/kernel/nmi.c 2003-01-28 10:29:56.000000000 +0100
@@ -29,6 +29,7 @@
static unsigned int nmi_hz = HZ;
unsigned int nmi_perfctr_msr; /* the MSR to reset in NMI handler */
extern void show_registers(struct pt_regs *regs);
+static int nmi_active;

#define K7_EVNTSEL_ENABLE (1 << 22)
#define K7_EVNTSEL_INT (1 << 20)
@@ -138,12 +139,10 @@

#ifdef CONFIG_PM

-#include <linux/pm.h>
-
-struct pm_dev *nmi_pmdev;
-
-static void disable_apic_nmi_watchdog(void)
+void disable_apic_nmi_watchdog(void)
{
+ if (!nmi_active)
+ return;
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_AMD:
wrmsr(MSR_K7_EVNTSEL0, 0, 0);
@@ -160,47 +159,10 @@
}
break;
}
+ nmi_active = 1;
}

-static int nmi_pm_callback(struct pm_dev *dev, pm_request_t rqst, void *data)
-{
- switch (rqst) {
- case PM_SUSPEND:
- disable_apic_nmi_watchdog();
- break;
- case PM_RESUME:
- setup_apic_nmi_watchdog();
- break;
- }
- return 0;
-}
-
-struct pm_dev * set_nmi_pm_callback(pm_callback callback)
-{
- apic_pm_unregister(nmi_pmdev);
- return apic_pm_register(PM_SYS_DEV, 0, callback);
-}
-
-void unset_nmi_pm_callback(struct pm_dev * dev)
-{
- apic_pm_unregister(dev);
- nmi_pmdev = apic_pm_register(PM_SYS_DEV, 0, nmi_pm_callback);
-}
-
-static void nmi_pm_init(void)
-{
- if (!nmi_pmdev)
- nmi_pmdev = apic_pm_register(PM_SYS_DEV, 0, nmi_pm_callback);
-}
-
-#define __pminit /*empty*/
-
-#else /* CONFIG_PM */
-
-static inline void nmi_pm_init(void) { }
-
-#define __pminit __init
-
+#define __pminit
#endif /* CONFIG_PM */

/*
@@ -314,7 +276,7 @@
default:
return;
}
- nmi_pm_init();
+ nmi_active = 1;
}

static spinlock_t nmi_print_lock = SPIN_LOCK_UNLOCKED;


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