| Message ID | afe397e3-c674-4dc3-9f3e-feea9275bb91@TX2EHSMHS023.ehs.local (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Quoting Soren Brinkmann (2013-04-16 10:06:50) > 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 <soren.brinkmann@xilinx.com> > --- > 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. > I've taken this patch for 3.11. Thanks, Mike > 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
On Tue, May 07, 2013 at 01:59:53PM -0700, Mike Turquette wrote: > Quoting Soren Brinkmann (2013-04-16 10:06:50) > > 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 <soren.brinkmann@xilinx.com> > > --- > > 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. > > > > I've taken this patch for 3.11. thank you. Sören
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)
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 <soren.brinkmann@xilinx.com> --- 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(-)