Messages in this thread |  | | | Date | Fri, 18 Jun 2010 23:21:55 -0700 (PDT) | | From | David Brownell <> | | Subject | Re: gpiolib and sleeping gpios |
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> > The runtime warnings will only show instances where the > non-sleeping > versions where called instead of the sleeping versions.
... *AND* the GPIO requires the cansleep() version...
Right; such calls are errors. We issue warnings since fault returns are inapplicable.
> There is no > warning to say that we are calling the spinlock safe > version, where it is possible to sleep.
The call context isn't what controls whether gpio_get_value() or gpio_get_value_cansleep() is appropriate ... it's the GPIO itself, and how its implementation works.
"possible to sleep" is a GPIO attribute, exposed by a predicate. If spinlock-safe calls are used on GPIOs with that attribute, a warning *IS* issued.
> > The point I was trying to make is that there are lots of > drivers which > will not work with gpios on sleeping io expanders because > they call the > spinlock safe gpio calls.
And they will trigger runtime warnings, and thus eventually get fixed. The way to do that is to check if the GPIO needs the cansleep() call
That's the first category above: the driver should have used the cansleep() variant, and sotriggers a runtime warning.
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