| Message ID | 1389702222-17260-2-git-send-email-ben.dooks@codethink.co.uk (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Tuesday, January 14, 2014 12:23:40 PM Ben Dooks wrote: > The drivers/base/power/clock_ops.c file is causing warnings from > the clock driver (as shown below) due to failing to do a clk_prepare() > call before enabling a clock. It also fails to check the balance of > prepare/unprepare as __pm_clk_remove() do clk_disable_unprepare() call. > > This bug has probably been in since commit b2476490e ("clk: introduce > the common clock framework") as the warning was part of the original > commit. It is strange that it has not been noticed (although this has > also been coupled with a failure for certain SH builds to not build the > necessary glue to use this method of controlling the clocks). > > In summary, this is probably needed in several stable branches but need > advice on which ones. > > On the Renesas Lager board, this causes numerous warnings of the following > and even worse the clock system will not enable clocks, causing drivers > that are in development to fail to work: > > WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:883 __clk_enable+0x2c/0xa0() All three queued up for 3.14, thanks! > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Pavel Machek <pavel@ucw.cz> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: linux-pm@vger.kernel.org > Cc: linux-sh@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > Reviewed-by: Ian Molton <ian.molton@codethink.co.uk> > --- > drivers/base/power/clock_ops.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c > index 9d8fde7..b9dd8fa 100644 > --- a/drivers/base/power/clock_ops.c > +++ b/drivers/base/power/clock_ops.c > @@ -43,6 +43,7 @@ static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce) > if (IS_ERR(ce->clk)) { > ce->status = PCE_STATUS_ERROR; > } else { > + clk_prepare(ce->clk); > ce->status = PCE_STATUS_ACQUIRED; > dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id); > } > @@ -99,10 +100,12 @@ static void __pm_clk_remove(struct pm_clock_entry *ce) > > if (ce->status < PCE_STATUS_ERROR) { > if (ce->status == PCE_STATUS_ENABLED) > - clk_disable_unprepare(ce->clk); > + clk_disable(ce->clk); > > - if (ce->status >= PCE_STATUS_ACQUIRED) > + if (ce->status >= PCE_STATUS_ACQUIRED) { > + clk_unprepare(ce->clk); > clk_put(ce->clk); > + } > } > > kfree(ce->con_id); >
diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c index 9d8fde7..b9dd8fa 100644 --- a/drivers/base/power/clock_ops.c +++ b/drivers/base/power/clock_ops.c @@ -43,6 +43,7 @@ static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce) if (IS_ERR(ce->clk)) { ce->status = PCE_STATUS_ERROR; } else { + clk_prepare(ce->clk); ce->status = PCE_STATUS_ACQUIRED; dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id); } @@ -99,10 +100,12 @@ static void __pm_clk_remove(struct pm_clock_entry *ce) if (ce->status < PCE_STATUS_ERROR) { if (ce->status == PCE_STATUS_ENABLED) - clk_disable_unprepare(ce->clk); + clk_disable(ce->clk); - if (ce->status >= PCE_STATUS_ACQUIRED) + if (ce->status >= PCE_STATUS_ACQUIRED) { + clk_unprepare(ce->clk); clk_put(ce->clk); + } } kfree(ce->con_id);
The drivers/base/power/clock_ops.c file is causing warnings from the clock driver (as shown below) due to failing to do a clk_prepare() call before enabling a clock. It also fails to check the balance of prepare/unprepare as __pm_clk_remove() do clk_disable_unprepare() call. This bug has probably been in since commit b2476490e ("clk: introduce the common clock framework") as the warning was part of the original commit. It is strange that it has not been noticed (although this has also been coupled with a failure for certain SH builds to not build the necessary glue to use this method of controlling the clocks). In summary, this is probably needed in several stable branches but need advice on which ones. On the Renesas Lager board, this causes numerous warnings of the following and even worse the clock system will not enable clocks, causing drivers that are in development to fail to work: WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:883 __clk_enable+0x2c/0xa0() Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-pm@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Reviewed-by: Ian Molton <ian.molton@codethink.co.uk> --- drivers/base/power/clock_ops.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)