Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH 01/48] clk: at91: replace usleep() by udelay() calls | Date | Mon, 13 Jun 2016 21:26:49 +0200 |
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On Monday, June 13, 2016 5:24:09 PM CEST Alexandre Belloni wrote: > On 11/06/2016 at 00:30:36 +0200, Arnd Bergmann wrote : > > On Saturday, June 11, 2016 12:03:04 AM CEST Alexandre Belloni wrote: > > > From: Cyrille Pitchen <cyrille.pitchen@atmel.com> > > > > > > Fix the main and slow clock .prepare() implementations which used to call > > > usleep() when the scheduler wasn't ready yet. > > > > > > > Does this have to be called that early? It seems wasteful to always > > call udelay() here, when these are functions that are normally > > allowed to sleep. > > > > So I've tested it and something like that would work: > > if (system_state < SYSTEM_RUNNING) > udelay(osc->startup_usec); > else > usleep_range(osc->startup_usec, osc->startup_usec + 1);
I think that's reasonable in this case.
> But I'm afraid it would be the first driver to actually do something > like that (however, it is already the only driver trying to sleep).
We have a lot of drivers that call potentially sleeping function from the .prepare callback, e.g. when they go to an i2c controller.
Arnd
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