From: Wei Ni <wni@xxxxxxxxxx> The dvfs will try to init clock, it trickles down to the child clock. Part of that init is to set cansleep flag. When setting a clock as cansleep, in which case the entire list of clocks is traversed to set the children as cansleep as well. in here, the clk_set_cansleep can only be called on clocks that are the sole parent of all of their child clocks, meaning the child clock can not be reparented onto a different, possibly non-sleeping, clock. If the child clock has the set_parent callback, the driver warns that this case is not proper, it will show WARNING: "can't make child clock xxx of xxx sleepable if it's parent could change" But Some clocks only has one parent, although they have set_parent callback. These clocks' flags is set to 0, not MUX, it means they can not be reparented. So we can remove this WARNING if !(flags & MUX). Signed-off-by: Wei Ni <wni@xxxxxxxxxx> --- v1: This patch against linux-tegra-2.6.37 branch in git://android.git.kernel.org/kernel/tegra.git arch/arm/mach-tegra/clock.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c index f556977..d0b6b45 100644 --- a/arch/arm/mach-tegra/clock.c +++ b/arch/arm/mach-tegra/clock.c @@ -187,7 +187,8 @@ static void __clk_set_cansleep(struct clk *c) if (child->parent != c) continue; - WARN(child->ops && child->ops->set_parent, + WARN(child->ops && child->ops->set_parent + && (child->flags & MUX), "can't make child clock %s of %s " "sleepable if it's parent could change", child->name, c->name); -- 1.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html