Messages in this thread | | | Date | Tue, 16 Jul 2013 17:13:24 +0200 | From | Thomas Petazzoni <> | Subject | Re: [PATCH v3 2/7] mmc: atmel-mci: prepare clk before calling enable |
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Dear Boris BREZILLON,
On Tue, 16 Jul 2013 17:06:48 +0200, Boris BREZILLON wrote:
> buf = kmalloc(ATMCI_REGS_SIZE, GFP_KERNEL); > if (!buf) > @@ -389,9 +391,13 @@ static int atmci_regs_show(struct seq_file *s, void *v) > * consistent. > */ > spin_lock_bh(&host->lock); > - clk_enable(host->mck); > + ret = clk_prepare_enable(host->mck);
I am not very familiar with the spin_lock_bh() variant, but are you sure we are allowed to sleep within a spin_lock_bh()-protected critical section?
Remember that clk_prepare_enable() calls both ->prepare() and ->enable() for the clock, and ->prepare() is allowed to sleep, while ->enable() is guaranteed not to sleep.
Therefore, clk_prepare() is usually called at probe time, while clk_enable() is called whenever enabling/disabling the clock is really needed. So not all clk_enable() can transparently be converted into a clk_prepare_enable().
Best regards,
Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com
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