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

Locking in the clk API

From: Saravana Kannan <hidden>
Date: 2011-01-24 19:31:01

On 01/22/2011 01:15 AM, Russell King - ARM Linux wrote:
On Fri, Jan 21, 2011 at 05:53:43PM -0800, Saravana Kannan wrote:
quoted
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.
I'm well aware of the fact that you can't grab a mutex inside a 
spinlock. Like I said, I will dig into this sometime and get back.

-Saravana

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help