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

From: Andy Lutomirski
Date: Sun Apr 11 2004 - 23:15:58 EST


Alex Williamson wrote:

On Sun, 2004-04-11 at 16:29, Matthew Wilcox wrote:

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,

Is there any reason this shouldn't be an ioctl?

--Andy

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