A clock's notifier count only reflects notifiers which are registered directly for that clock. A reparent operation though affects the whole subtree because of a potential rate change. When issuing the pre rate change notifications only the notifier count for the clock to be changed is considered and notifiers for subclocks may never be called. Resulting in clocks in the subtree which have registered notifiers, may receive a POST_- or ABORT_RATE_CHANGE notification, without a PRE_RATE_CHANGE_NOTIFICATION. Therefore always traverse the whole subtree when issueing pre rate change notifications during a reparent operation.
Signed-off-by: Soren Brinkmann <[email protected]> --- This should probably be considered an RFC. There may be smarter ways to resolve this issue. E.g. forward notifier counts upstream the way it is done with enable counts. Sören drivers/clk/clk.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 20ce67f..1179cb5 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1481,8 +1481,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent) } /* propagate PRE_RATE_CHANGE notifications */ - if (clk->notifier_count) - ret = __clk_speculate_rates(clk, p_rate); + ret = __clk_speculate_rates(clk, p_rate); /* abort if a driver objects */ if (ret & NOTIFY_STOP_MASK) -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
