i8254_restore is called from apm_default_resume() to reload

the countdown register.
this should not be necessary but there are broken laptops that
do not restore the countdown register on resume.
when it happnes, it messes up the hardclock interval and system clock,
which leads to the infamous "calcru: negative time" problem.

Submitted by:	kjc, iwasaki
Reviewed by:	Steve O'Hara-Smith <steveo@eircom.net> and committers.
Obtained from:	PAO3

sys/amd64/amd64/tsc.c

@@ -690,6 +690,28 @@ set_timer_freq(u_int freq, int intr_freq)
 	write_eflags(ef);
 }
 
+/*
+ * i8254_restore is called from apm_default_resume() to reload
+ * the countdown register.
+ * this should not be necessary but there are broken laptops that
+ * do not restore the countdown register on resume.
+ * when it happnes, it messes up the hardclock interval and system clock,
+ * which leads to the infamous "calcru: negative time" problem.
+ */
+void
+i8254_restore(void)
+{
+	u_long ef;
+
+	ef = read_eflags();
+	disable_intr();
+	outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+	outb(TIMER_CNTR0, timer0_max_count & 0xff);
+	outb(TIMER_CNTR0, timer0_max_count >> 8);
+	CLOCK_UNLOCK();
+	write_eflags(ef);
+}
+
 /*
  * Initialize 8254 timer 0 early so that it can be used in DELAY().
  * XXX initialization of other timers is unintentionally left blank.

sys/amd64/include/clock.h

@@ -44,6 +44,7 @@ int	acquire_timer1 __P((int mode));
 int	release_timer1 __P((void));
 #endif
 int	sysbeep __P((int pitch, int period));
+void	i8254_restore __P((void));
 
 #endif /* KERNEL */
 

sys/amd64/isa/clock.c

@@ -690,6 +690,28 @@ set_timer_freq(u_int freq, int intr_freq)
 	write_eflags(ef);
 }
 
+/*
+ * i8254_restore is called from apm_default_resume() to reload
+ * the countdown register.
+ * this should not be necessary but there are broken laptops that
+ * do not restore the countdown register on resume.
+ * when it happnes, it messes up the hardclock interval and system clock,
+ * which leads to the infamous "calcru: negative time" problem.
+ */
+void
+i8254_restore(void)
+{
+	u_long ef;
+
+	ef = read_eflags();
+	disable_intr();
+	outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+	outb(TIMER_CNTR0, timer0_max_count & 0xff);
+	outb(TIMER_CNTR0, timer0_max_count >> 8);
+	CLOCK_UNLOCK();
+	write_eflags(ef);
+}
+
 /*
  * Initialize 8254 timer 0 early so that it can be used in DELAY().
  * XXX initialization of other timers is unintentionally left blank.

sys/i386/apm/apm.c

@@ -404,6 +404,7 @@ apm_default_resume(void *arg)
 
 	/* modified for adjkerntz */
 	pl = splsoftclock();
+	i8254_restore();		/* restore timer_freq and hz */
 	inittodr(0);			/* adjust time to RTC */
 	microtime(&resume_time);
 	getmicrotime(&tmp_time);

sys/i386/bios/apm.c

@@ -404,6 +404,7 @@ apm_default_resume(void *arg)
 
 	/* modified for adjkerntz */
 	pl = splsoftclock();
+	i8254_restore();		/* restore timer_freq and hz */
 	inittodr(0);			/* adjust time to RTC */
 	microtime(&resume_time);
 	getmicrotime(&tmp_time);

sys/i386/i386/tsc.c

@@ -690,6 +690,28 @@ set_timer_freq(u_int freq, int intr_freq)
 	write_eflags(ef);
 }
 
+/*
+ * i8254_restore is called from apm_default_resume() to reload
+ * the countdown register.
+ * this should not be necessary but there are broken laptops that
+ * do not restore the countdown register on resume.
+ * when it happnes, it messes up the hardclock interval and system clock,
+ * which leads to the infamous "calcru: negative time" problem.
+ */
+void
+i8254_restore(void)
+{
+	u_long ef;
+
+	ef = read_eflags();
+	disable_intr();
+	outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+	outb(TIMER_CNTR0, timer0_max_count & 0xff);
+	outb(TIMER_CNTR0, timer0_max_count >> 8);
+	CLOCK_UNLOCK();
+	write_eflags(ef);
+}
+
 /*
  * Initialize 8254 timer 0 early so that it can be used in DELAY().
  * XXX initialization of other timers is unintentionally left blank.

sys/i386/include/clock.h

@@ -44,6 +44,7 @@ int	acquire_timer1 __P((int mode));
 int	release_timer1 __P((void));
 #endif
 int	sysbeep __P((int pitch, int period));
+void	i8254_restore __P((void));
 
 #endif /* KERNEL */
 

sys/i386/isa/clock.c

@@ -690,6 +690,28 @@ set_timer_freq(u_int freq, int intr_freq)
 	write_eflags(ef);
 }
 
+/*
+ * i8254_restore is called from apm_default_resume() to reload
+ * the countdown register.
+ * this should not be necessary but there are broken laptops that
+ * do not restore the countdown register on resume.
+ * when it happnes, it messes up the hardclock interval and system clock,
+ * which leads to the infamous "calcru: negative time" problem.
+ */
+void
+i8254_restore(void)
+{
+	u_long ef;
+
+	ef = read_eflags();
+	disable_intr();
+	outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+	outb(TIMER_CNTR0, timer0_max_count & 0xff);
+	outb(TIMER_CNTR0, timer0_max_count >> 8);
+	CLOCK_UNLOCK();
+	write_eflags(ef);
+}
+
 /*
  * Initialize 8254 timer 0 early so that it can be used in DELAY().
  * XXX initialization of other timers is unintentionally left blank.

sys/isa/atrtc.c

@@ -690,6 +690,28 @@ set_timer_freq(u_int freq, int intr_freq)
 	write_eflags(ef);
 }
 
+/*
+ * i8254_restore is called from apm_default_resume() to reload
+ * the countdown register.
+ * this should not be necessary but there are broken laptops that
+ * do not restore the countdown register on resume.
+ * when it happnes, it messes up the hardclock interval and system clock,
+ * which leads to the infamous "calcru: negative time" problem.
+ */
+void
+i8254_restore(void)
+{
+	u_long ef;
+
+	ef = read_eflags();
+	disable_intr();
+	outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+	outb(TIMER_CNTR0, timer0_max_count & 0xff);
+	outb(TIMER_CNTR0, timer0_max_count >> 8);
+	CLOCK_UNLOCK();
+	write_eflags(ef);
+}
+
 /*
  * Initialize 8254 timer 0 early so that it can be used in DELAY().
  * XXX initialization of other timers is unintentionally left blank.