Thread (86 messages) 86 messages, 20 authors, 2011-01-28

Locking in the clk API

From: Russell King - ARM Linux <hidden>
Date: 2011-01-22 09:15:26

On Fri, Jan 21, 2011 at 05:53:43PM -0800, Saravana Kannan wrote:
On 01/21/2011 01:32 AM, Russell King - ARM Linux wrote:
quoted
On Thu, Jan 20, 2011 at 08:12:45PM -0800, Saravana Kannan wrote:
quoted
In my opinion, the only major reason for needing atomic clk APIs was due
to device_ops->suspend being atomic. Since that's not the case anymore,
I really don't see a justification for atomic clocks. Sure, I might have
missed some exceptions, but in that case we should make the atomic APIs
an exception (add clk_enable_atomic) and not the norm.
The suspend method has never been atomic.  It has always been able to
sleep.  You're mistaken.
I distinctly remember trying to do sleeping stuff inside a .suspend  
function and have it complain that it's atomic. So, I think you might be  
mistaken.
No I'm not.  I've always had stuff which takes mutexes/semaphores in
the suspend method.

You'll get the warning if you take a spinlock and then try sleeping -
but that's your error for creating an atomic context (you can't sleep
while holding a spinlock), not the fault of the callback.
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