Re: [PATCH 1/3] si2157: change command for sleep

[Antti Palosaari <crope@iki.fi>]

On 09/18/2014 02:50 PM, Mauro Carvalho Chehab wrote:
> Sorry, I misunderstood this patch.
>
> There are actually two different things, each requiring a different PM
> setting:
>
> 1) to put the tuner to sleep while it is not in usage;
>
> 2) put the machine to suspend.
>
> This patch is for (1). That's FINE. I'll apply it.
>
> Yet, for (2), assuming a suspend to ram, the best is to save more
> power.
>
> In the past, the DVB core didn't make any distinction between those
> two, but we recently added a hook for suspend there.
>
> So, it makes sense to keep the tuner powerdown mode for suspend.


I think old deep sleep should be used for suspend, whilst on warm state 
that new is OK.

I2C driver has suspend/resume support and it is one thing I am going to 
study in near future. Currently I have 128GB SSD and no swap at all, so 
I cannot test it now. I have already bought 256GB SSD and I am just 
waiting for Fedora 21 alpha version, which I will install with proper 
swap. Unfortunately they have delayed many times already Fedora 21 alpha...

I am not even sure if DVB frontend needs any special suspend/resume 
handling, isn't it possible to use standard kernel PM here? (I already 
added some initial PM to DVB FE ~2 years ago, but IIRC those will only 
kill threads and so which are not allowed when suspend).

So is there some reason DVB FE needs suspend/resume hooks?


regards
Antti

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