Messages in this thread | | | Date | Tue, 03 May 2011 10:00:58 -0700 | From | Stephen Boyd <> | Subject | Re: [Update x3][PATCH 7/9] PM / Runtime: Generic clock manipulation rountines for runtime PM (v6) |
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On 04/29/2011 03:04 PM, Rafael J. Wysocki wrote: > + > +/** > + * enable_clock - Enable a device clock. > + * @dev: Device whose clock is to be enabled. > + * @con_id: Connection ID of the clock. > + */ > +static void enable_clock(struct device *dev, const char *con_id) > +{ > + struct clk *clk; > + > + clk = clk_get(dev, con_id); > + if (!IS_ERR(clk)) { > + clk_enable(clk); > + clk_put(clk); > + dev_info(dev, "Runtime PM disabled, clock forced on.\n"); > + } > +}
This doesn't make much sense to me. You're getting a clock and then enabling it and then putting the clock? How can you be so sure that clk_put() won't one day do some kind of lower power mode on the clock when clk_put() is called on it? I don't think anyone does anything today, but I don't think its safe to assume that clk_put() won't try to forcibly shut off the clock once all clk_get() callers have clk_put().
Perhaps we should document the meaning of clk_enable() followed by clk_put() somewhere instead?
> + > +/** > + * disable_clock - Disable a device clock. > + * @dev: Device whose clock is to be disabled. > + * @con_id: Connection ID of the clock. > + */ > +static void disable_clock(struct device *dev, const char *con_id) > +{ > + struct clk *clk; > + > + clk = clk_get(dev, con_id); > + if (!IS_ERR(clk)) { > + clk_disable(clk); > + clk_put(clk); > + dev_info(dev, "Runtime PM disabled, clock forced off.\n"); > + } > +}
This might not be as bad, but it looks like a similar problem.
> - > -static int platform_bus_notify(struct notifier_block *nb, > - unsigned long action, void *data) > -{ > - struct device *dev = data; > - struct clk *clk; > - > - dev_dbg(dev, "platform_bus_notify() %ld !\n", action); > - > - switch (action) { > - case BUS_NOTIFY_BIND_DRIVER: > - clk = clk_get(dev, NULL); > - if (!IS_ERR(clk)) { > - clk_enable(clk); > - clk_put(clk); > - dev_info(dev, "runtime pm disabled, clock forced on\n"); > - } > - break; > - case BUS_NOTIFY_UNBOUND_DRIVER: > - clk = clk_get(dev, NULL); > - if (!IS_ERR(clk)) { > - clk_disable(clk); > - clk_put(clk); > - dev_info(dev, "runtime pm disabled, clock forced off\n"); > - }
Ah ok I see that it's coming from here.
BTW, whatever is in linux-next is failing to compile:
drivers/base/power/clock_ops.c:391: error: 'con_id' undeclared (first use in this function) drivers/base/power/clock_ops.c:391: error: (Each undeclared identifier is reported only once drivers/base/power/clock_ops.c:391: error: for each function it appears in.)
-- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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