On Wed, Apr 12, 2017 at 09:46:05AM -0700, Stephen Boyd wrote: > On 03/21, Peter De Schrijver wrote: > > Whenever a user change its min or max rate limit of a clock, we need to > > re-evaluate the current clock rate and possibly change it if the new limits > > require so. To do this clk_set_rate_range() already calls > > clk_core_set_rate_nolock, however this won't have the intended effect > > because the core clock rate hasn't changed. To fix this, move the test to > > avoid setting the same core clock rate again, to clk_set_rate() so > > clk_core_set_rate_nolock() can change the clock rate when min or max have > > been updated, even when the core clock rate has not changed. > > I'd expect some sort of Fixes: tag here? Or it never worked!?
I don't think this ever worked. > > > > > Signed-off-by: Peter De Schrijver <[email protected]> > > I seem to recall some problems here around rate aggregation that > we fixed after the patches merged. Sorry, but I have to go back > and look at those conversations to refresh my memory and make > sure this is all fine. > > Are you relying on the rate setting op to be called with the new > min/max requirements if the aggregated rate is the same? I don't > understand why clk drivers care. > No. But I do rely on the rate setting op to be called when a new min or max rate would cause the rate to be changed even when there is no new rate request. Eg: min = 100MHz, max = 500MHz, current rate request is 400MHz, then max changes to 300MHz. Today the rate setting op will not be called, while I think it should be called to lower the rate to 300MHz. Peter. > > --- > > drivers/clk/clk.c | 13 +++++++------ > > 1 file changed, 7 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > > index 2fa2fb8..0b815d1 100644 > > --- a/drivers/clk/clk.c > > +++ b/drivers/clk/clk.c > > @@ -1569,10 +1569,6 @@ static int clk_core_set_rate_nolock(struct clk_core > > *core, > > if (!core) > > return 0; > > > > - /* bail early if nothing to do */ > > - if (rate == clk_core_get_rate_nolock(core)) > > - return 0; > > - > > if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count) > > return -EBUSY; > > > > @@ -1621,16 +1617,21 @@ static int clk_core_set_rate_nolock(struct clk_core > > *core, > > */ > > int clk_set_rate(struct clk *clk, unsigned long rate) > > { > > - int ret; > > + int ret = 0; > > > > if (!clk) > > - return 0; > > + return ret; > > Why? Noise? > > > > > /* prevent racing with updates to the clock topology */ > > clk_prepare_lock(); > > > > + /* bail early if nothing to do */ > > + if (rate == clk_core_get_rate_nolock(clk->core)) > > + goto out; > > + > > ret = clk_core_set_rate_nolock(clk->core, rate); > > > > +out: > > clk_prepare_unlock(); > > > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project
