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-rw-r--r--arch/arm/mach-omap2/pm44xx.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/arch/arm/mach-omap2/pm44xx.c b/arch/arm/mach-omap2/pm44xx.c
index aa6fd98f606e..ea62e75ef21d 100644
--- a/arch/arm/mach-omap2/pm44xx.c
+++ b/arch/arm/mach-omap2/pm44xx.c
@@ -77,10 +77,20 @@ static int omap4_pm_suspend(void)
omap_set_pwrdm_state(pwrst->pwrdm, pwrst->saved_state);
pwrdm_set_logic_retst(pwrst->pwrdm, pwrst->saved_logic_state);
}
- if (ret)
+ if (ret) {
pr_crit("Could not enter target state in pm_suspend\n");
- else
+ /*
+ * OMAP4 chip PM currently works only with certain (newer)
+ * versions of bootloaders. This is due to missing code in the
+ * kernel to properly reset and initialize some devices.
+ * Warn the user about the bootloader version being one of the
+ * possible causes.
+ * http://www.spinics.net/lists/arm-kernel/msg218641.html
+ */
+ pr_warn("A possible cause could be an old bootloader - try u-boot >= v2012.07\n");
+ } else {
pr_info("Successfully put all powerdomains to target state\n");
+ }
return 0;
}
@@ -146,6 +156,13 @@ int __init omap4_pm_init(void)
}
pr_err("Power Management for TI OMAP4.\n");
+ /*
+ * OMAP4 chip PM currently works only with certain (newer)
+ * versions of bootloaders. This is due to missing code in the
+ * kernel to properly reset and initialize some devices.
+ * http://www.spinics.net/lists/arm-kernel/msg218641.html
+ */
+ pr_warn("OMAP4 PM: u-boot >= v2012.07 is required for full PM support\n");
ret = pwrdm_for_each(pwrdms_setup, NULL);
if (ret) {