On 09/06/2014 06:17 AM, Mauro Carvalho Chehab wrote:
Em Sat, 06 Sep 2014 06:10:01 +0300
Antti Palosaari <crope@xxxxxx> escreveu:
... I simply don't understand why you want hook that RF strength call
via demod? The frontend cache is shared between demod and tuner. We use
it for tuner driver as well demod driver. Let the tuner driver make RSSI
calculation independently without any unneeded relation to demod driver.
Well, adding kthreads has a cost, with is a way higher than just
calling a callback function.
Also, it makes a way more complicated to implement several tasks.
For example, devices with kthreads need to stop them during suspend,
and restart them at resume time, or otherwise suspend and/or resume
may not work.
Also, the power consumption increases with kthread, as the CPU need
to be periodically waken.
I'm not saying we shouldn't use kthreads at driver level, but
the best is to avoid when there are some other simpler ways of doing it.
And small reality check, how much you think one kthreads, that polls
once per 2 second or so causes, in a case when you are *already
streaming* 20-80 Mbit/sec data stream :) I think CPU does not need wake
up to execute one thread as there is a lot of other interrupts happening
in that use case anyway.
We have a remote controller which is polled often as 100ms and it
happens even when device is "sleeping".
regards
Antti
--
http://palosaari.fi/
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