Re: PROBLEM: Can't boot a (HZ = 1000) kernel using an AMD Phenom-II processor

Andreas Herrmann
2009-02-20T22:29:37Z

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Mark,

Here we go ...

Attached is a compound version against v2.6.28.4 of some
hpet patches that I'd like to submit asap.

Can you please apply this patch and test it on your machine.

By chance I've found a machine wich also hangs with HZ_1000.
And this patch fixes the problem on this machine.

Regards,
Andreas

PS: Please boot with "hpet=verbose" to show the HPET registers
(no additional debug parameter needed this time).

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diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c9115c1..a6a4134 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -485,10 +485,12 @@ and is between 256 and 4096 characters. It is defined in the file
Default: 64

hpet= [X86-32,HPET] option to control HPET usage
- Format: { enable (default) | disable | force }
+ Format: { enable (default) | disable | force |
+ verbose }
disable: disable HPET and use PIT instead
force: allow force enabled of undocumented chips (ICH4,
VIA, nVidia)
+ verbose: show contents of HPET registers during setup

com20020= [HW,NET] ARCnet - COM20020 chipset
Format:
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 067d8de..85366b2 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -78,6 +78,7 @@ static inline void hpet_clear_mapping(void)
*/
static int boot_hpet_disable;
int hpet_force_user;
+static int hpet_verbose;

static int __init hpet_setup(char *str)
{
@@ -86,6 +87,8 @@ static int __init hpet_setup(char *str)
boot_hpet_disable = 1;
if (!strncmp("force", str, 5))
hpet_force_user = 1;
+ if (!strncmp("verbose", str, 7))
+ hpet_verbose = 1;
}
return 1;
}
@@ -117,6 +120,43 @@ int is_hpet_enabled(void)
}
EXPORT_SYMBOL_GPL(is_hpet_enabled);

+static void _hpet_print_config(const char *function, int line)
+{
+ u32 i, timers, l, h;
+ printk(KERN_INFO "hpet: %s(%d):\n", function, line);
+ l = hpet_readl(HPET_ID);
+ h = hpet_readl(HPET_PERIOD);
+ timers = ((l & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
+ printk(KERN_INFO "hpet: ID: 0x%x, PERIOD: 0x%x\n", l, h);
+ l = hpet_readl(HPET_CFG);
+ h = hpet_readl(HPET_STATUS);
+ printk(KERN_INFO "hpet: CFG: 0x%x, STATUS: 0x%x\n", l, h);
+ l = hpet_readl(HPET_COUNTER);
+ h = hpet_readl(HPET_COUNTER+4);
+ printk(KERN_INFO "hpet: COUNTER_l: 0x%x, COUNTER_h: 0x%x\n", l, h);
+
+ for (i = 0; i < timers; i++) {
+ l = hpet_readl(HPET_Tn_CFG(i));
+ h = hpet_readl(HPET_Tn_CFG(i)+4);
+ printk(KERN_INFO "hpet: T%d: CFG_l: 0x%x, CFG_h: 0x%x\n",
+ i, l, h);
+ l = hpet_readl(HPET_Tn_CMP(i));
+ h = hpet_readl(HPET_Tn_CMP(i)+4);
+ printk(KERN_INFO "hpet: T%d: CMP_l: 0x%x, CMP_h: 0x%x\n",
+ i, l, h);
+ l = hpet_readl(HPET_Tn_ROUTE(i));
+ h = hpet_readl(HPET_Tn_ROUTE(i)+4);
+ printk(KERN_INFO "hpet: T%d ROUTE_l: 0x%x, ROUTE_h: 0x%x\n",
+ i, l, h);
+ }
+}
+
+#define hpet_print_config() \
+do { \
+ if (hpet_verbose) \
+ _hpet_print_config(__FUNCTION__, __LINE__); \
+} while (0)
+
/*
* When the hpet driver (/dev/hpet) is enabled, we need to reserve
* timer 0 and timer 1 in case of RTC emulation.
@@ -189,27 +229,37 @@ static struct clock_event_device hpet_clockevent = {
.rating = 50,
};

-static void hpet_start_counter(void)
+static void hpet_stop_counter(void)
{
unsigned long cfg = hpet_readl(HPET_CFG);
-
cfg &= ~HPET_CFG_ENABLE;
hpet_writel(cfg, HPET_CFG);
hpet_writel(0, HPET_COUNTER);
hpet_writel(0, HPET_COUNTER + 4);
+}
+
+static void hpet_start_counter(void)
+{
+ unsigned long cfg = hpet_readl(HPET_CFG);
cfg |= HPET_CFG_ENABLE;
hpet_writel(cfg, HPET_CFG);
}

+static void hpet_restart_counter(void)
+{
+ hpet_stop_counter();
+ hpet_start_counter();
+}
+
static void hpet_resume_device(void)
{
force_hpet_resume();
}

-static void hpet_restart_counter(void)
+static void hpet_resume_counter(void)
{
hpet_resume_device();
- hpet_start_counter();
+ hpet_restart_counter();
}

static void hpet_enable_legacy_int(void)
@@ -257,27 +307,21 @@ static int hpet_setup_msi_irq(unsigned int irq);
static void hpet_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt, int timer)
{
- unsigned long cfg, cmp, now;
+ unsigned long cfg;
uint64_t delta;

switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
+ hpet_stop_counter();
delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * evt->mult;
delta >>= evt->shift;
- now = hpet_readl(HPET_COUNTER);
- cmp = now + (unsigned long) delta;
cfg = hpet_readl(HPET_Tn_CFG(timer));
cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
HPET_TN_SETVAL | HPET_TN_32BIT;
hpet_writel(cfg, HPET_Tn_CFG(timer));
- /*
- * The first write after writing TN_SETVAL to the
- * config register sets the counter value, the second
- * write sets the period.
- */
- hpet_writel(cmp, HPET_Tn_CMP(timer));
- udelay(1);
hpet_writel((unsigned long) delta, HPET_Tn_CMP(timer));
+ hpet_start_counter();
+ hpet_print_config();
break;

case CLOCK_EVT_MODE_ONESHOT:
@@ -304,6 +348,7 @@ static void hpet_set_mode(enum clock_event_mode mode,
irq_set_affinity(hdev->irq, cpumask_of_cpu(hdev->cpu));
enable_irq(hdev->irq);
}
+ hpet_print_config();
break;
}
}
@@ -522,6 +567,7 @@ static void hpet_msi_capability_lookup(unsigned int start_timer)

num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
num_timers++; /* Value read out starts from 0 */
+ hpet_print_config();

hpet_devs = kzalloc(sizeof(struct hpet_dev) * num_timers, GFP_KERNEL);
if (!hpet_devs)
@@ -690,7 +736,7 @@ static struct clocksource clocksource_hpet = {
.mask = HPET_MASK,
.shift = HPET_SHIFT,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
- .resume = hpet_restart_counter,
+ .resume = hpet_resume_counter,
#ifdef CONFIG_X86_64
.vread = vread_hpet,
#endif
@@ -702,7 +748,7 @@ static int hpet_clocksource_register(void)
cycle_t t1;

/* Start the counter */
- hpet_start_counter();
+ hpet_restart_counter();

/* Verify whether hpet counter works */
t1 = read_hpet();
@@ -788,6 +834,7 @@ int __init hpet_enable(void)
* information and the number of channels
*/
id = hpet_readl(HPET_ID);
+ hpet_print_config();

#ifdef CONFIG_HPET_EMULATE_RTC
/*
@@ -839,6 +886,7 @@ static __init int hpet_late_init(void)
}

hpet_reserve_platform_timers(hpet_readl(HPET_ID));
+ hpet_print_config();

for_each_online_cpu(cpu) {
hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu);