Messages in this thread | | | Date | Wed, 15 May 2013 21:17:03 -0700 | From | Saravana Kannan <> | Subject | Re: [PATCH] clk: Fix race condition between clk_set_parent and clk_enable() |
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On 05/15/2013 12:24 PM, Ulf Hansson wrote: > On 1 May 2013 06:42, Saravana Kannan <skannan@codeaurora.org> wrote:
<snip>
>> - /* migrate prepare */ >> - if (clk->prepare_count) >> + /* >> + * Migrate prepare state between parents and prevent race with >> + * clk_enable(). >> + * >> + * If the clock is not prepared, then a race with >> + * clk_enable/disable() is impossible since we already have the >> + * prepare lock (future calls to clk_enable() need to be preceded by >> + * a clk_prepare()). >> + * >> + * If the clock is prepared, migrate the prepared state to the new >> + * parent and also protect against a race with clk_enable() by >> + * forcing the clock and the new parent on. This ensures that all >> + * future calls to clk_enable() are practically NOPs with respect to >> + * hardware and software states. >> + */ > > Maybe an additional note about that since CLK_SET_PARENT_GATE is a > prerequisite for doing migration of "prepare", we also interpreted > this flags as it is acceptable to enable the clock(s) in this context.
Done. Sent v2 patch.
<snip>
> > Looks good! Thanks for having another round to fixup this kind of > tricky code. :-)
Thanks :-)
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> >
Thanks again.
-Saravana
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