On Mon, Dec 14, 2009 at 13:37, Johannes Stezenbach <js@xxxxxxxxx> wrote:
> On Mon, Dec 14, 2009 at 11:34:31AM +0100, Kay Sievers wrote:
>> On Mon, Dec 14, 2009 at 11:28, Johannes Stezenbach <js@xxxxxxxxx> wrote:
>> > On Mon, Dec 14, 2009 at 10:14:50AM +0100, Martin Pitt wrote:
>> >>
>> >> A gotcha that I see here is that the force_release only ever gets
>> >> appended to. I. e. whenever we run udevtrigger, we'd append the same
>> >> keys again. POSIX shell doesn't have elaborate substring matching
>> >> capabilities like bash's ${x/pattern/string}, so it might not be too
>> >> easy to check if we already have a key in POSIX sh. (But please don't
>> >> call grep in a loop; let's rather rewrite this bit in C). There might
>> >> be some trickery with splitting by IFS=, into an array or so, if you
>> >> want to keep using sh?
>> >
>> > The problem is that force_release is preset by the kernel, so
>> > in order to do what you want we need either
>> > a) pass both old and new key list on "change"
>> > b) save initial force_release value to a file on "add"
>> > and use the file on "change"
>>
>> It should just not mangle the sysfs string if the value is already
>> contained. Why would you need to store anything between a "change" and
>> "add" event? Both events are handled the same way, and the two
>> independent events run one after each other.
>
> I don't understand. I only append to the force_release attribute
> because the kernel already removes duplicates.
Ah, cool.
> However, what does not work this way is to remove scancodes from
> force_release. I thought that was what Martin wanted to accomplish
> on the "change" event.
I don't think we really need to care about that. It thought it was
only the pattern ACTION="add|change", which is pretty common.
>> I guess the logic to append a value to the sysfs string only if needed
>> should be done in a tine C program, or a sed script with a RUN+= call
>> directly to sed maybe can be used ...
>
> sed cannot do hex to decimal conversion, but awk could be used.
Ah, that may be fine, if that works with a single commandline passed by RUN.
Thanks,
Kay
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