patch-2.4.22 linux-2.4.22/arch/ppc/kernel/idle_gen.c

• Lines: 42
• Date: 2003-08-25 04:44:40.000000000 -0700
• Orig file: linux-2.4.21/arch/ppc/kernel/idle_gen.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/arch/ppc/kernel/idle_gen.c linux-2.4.22/arch/ppc/kernel/idle_gen.c
@@ -0,0 +1,41 @@
+/*
+ * This is the old power_save() function from idle.c:
+ *
+ * Written by Cort Dougan (cort@cs.nmt.edu)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+#include <linux/sched.h>
+#include <asm/processor.h>
+#include <asm/cputable.h>
+
+void power_save(void)
+{
+	/* Make sure the CPU has the DOZE feature set. */
+	if (!(cur_cpu_spec[smp_processor_id()]->cpu_features
+				& CPU_FTR_CAN_DOZE))
+		return;
+	/*
+	 * Disable interrupts to prevent a lost wakeup
+	 * when going to sleep.  This is necessary even with
+	 * RTLinux since we are not guaranteed an interrupt
+	 * didn't come in and is waiting for a __sti() before
+	 * emulating one.  This way, we really do hard disable.
+	 *
+	 * We assume that we're sti-ed when we come in here.  We
+	 * are in the idle loop so if we're cli-ed then it's a bug
+	 * anyway.
+	 *  -- Cort
+	 */
+	_nmask_and_or_msr(MSR_EE, 0);
+	if (!current->need_resched) {
+		/* set the POW bit in the MSR, and enable interrupts
+		 * so we wake up sometime! */
+		_nmask_and_or_msr(0, MSR_POW | MSR_EE);
+	}
+	_nmask_and_or_msr(0, MSR_EE);
+}