x86/time: Unconditionally register legacy timer interrupt

Peter Zijlstra · KAGA-KOKO · commit 6d671e1b85c6 · 2018-01-14T20:18:23.000+01:00
Even without a PIC/PIT the legacy timer interrupt is required for HPET in legacy replacement mode. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: len.brown@intel.com Cc: rui.zhang@intel.com Link: https://lkml.kernel.org/r/20171222092243.382623763@infradead.org
diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
@@ -69,9 +69,12 @@ static struct irqaction irq0  = {
 
 static void __init setup_default_timer_irq(void)
 {
-	if (!nr_legacy_irqs())
-		return;
-	setup_irq(0, &irq0);
+	/*
+	 * Unconditionally register the legacy timer; even without legacy
+	 * PIC/PIT we need this for the HPET0 in legacy replacement mode.
+	 */
+	if (setup_irq(0, &irq0))
+		pr_info("Failed to register legacy timer interrupt\n");
 }
 
 /* Default timer init function */

Original file line number	Diff line number	Diff line change
`@@ -69,9 +69,12 @@ static struct irqaction irq0 = {`
`69`	`69`
`70`	`70`	`static void __init setup_default_timer_irq(void)`
`71`	`71`	`{`
`72`		`- if (!nr_legacy_irqs())`
`73`		`- return;`
`74`		`- setup_irq(0, &irq0);`
	`72`	`+ /*`
	`73`	`+ * Unconditionally register the legacy timer; even without legacy`
	`74`	`+ * PIC/PIT we need this for the HPET0 in legacy replacement mode.`
	`75`	`+ */`
	`76`	`+ if (setup_irq(0, &irq0))`
	`77`	`+ pr_info("Failed to register legacy timer interrupt\n");`
`75`	`78`	`}`
`76`	`79`
`77`	`80`	`/* Default timer init function */`