Re: [ACPI] Re: [PATCH] filling in ACPI method access via sysfs namespace

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > It seems unintuitive that you have to read the file for the method to
> > take effect.  How about having the write function invoke the method and
> > (if there is a result) store it for later read-back via the read function?
> > It should be discarded on close, of course.  A read() on a file with
> > no stored result should invoke the ACPI method (on the assumption this
> > is a parameter-less method) and return the result directly.  Closing a
> > file should discard any result from the method.
> 
>    How's this?  It behaves the way you described, but might be doing
> some questionable things with the buffer to get there.  Is there a
> better place to store the return data than back into the buf passed to
> write() (aka file->private_data)?  Without adding callbacks to
> open/close, I'm not sure how else we can dispose of the results on
> close.  Thanks,


> +	/*
> +	 * For convenience, handle cases where the last argument
> +	 * is too small.
> +	 */
> +	count = length / sizeof(union acpi_object);
> +	if (length % sizeof(union acpi_object))
> +		count++;
> +
> +	if (count) {
> +		size = sizeof(struct acpi_object_list) +
> +		       ((count - 1) * sizeof(union acpi_object *));

This probably makes it *way* too implementation dependand.
								Pavel
-- 
When do you have heart between your knees?