Hi Stephen, Mike,
On Mon, May 24, 2021 at 02:48:11PM +0200, Maxime Ripard wrote:
Hi Stephen, Mike,
On Mon, May 03, 2021 at 10:32:21AM +0200, Maxime Ripard wrote:
Hi Stephen,
On Fri, Apr 30, 2021 at 01:59:39PM -0700, Stephen Boyd wrote:
Quoting Maxime Ripard (2021-04-13 03:13:18)
Hi,
This is a follow-up of the discussion here: https://lore.kernel.org/linux-clk/20210319150355.xzw7ikwdaga2dwhv@gilmour/
This implements a mechanism to raise and lower clock rates based on consumer workloads, with an example of such an implementation for the RaspberryPi4 HDMI controller.
There's a couple of things worth discussing:
The name is in conflict with clk_request_rate, and even though it feels like the right name to me, we should probably avoid any confusion
The code so far implements a policy of always going for the lowest rate possible. While we don't have an use-case for something else, this should maybe be made more flexible?
I'm definitely confused how it is different from the clk_set_rate_exclusive() API and associated clk_rate_exclusive_get()/clk_rate_exclusive_put(). Can you explain further the differences in the cover letter here?
The exclusive API is meant to prevent the clock rate from changing, allowing a single user to make sure that no other user will be able to change it.
What we want here is instead to allow multiple users to be able to express a set of minimum rates and then let the CCF figure out a rate for that clock that matches those constraints (so basically what clk_set_min_rate does), but then does allow for the clock to go back to its initial rate once that constraint is not needed anymore.
So I guess it's more akin to clk_set_min_rate with rollback than the exclusive API?
Is that rationale good enough, or did you expect something else?
I'm not really sure what to do at this point. It's been over 2 months since I sent this series, and we really need that mechanism in some form or another.
I'm really fine with changing that series in any way, but I got no comment that I could address to turn this into something that would be acceptable to you. How can we move this forward?
Maxime