[Kde-hardware-devel] Re: Help needed: Make libsolid 4.6 running without HAL

[Kevin Ottens]

On Wednesday 10 November 2010 03:35:53 Rafael Fernández López wrote:
> I have been working today on the UDev backend to get it in shape. Some
> comments:
> 
> I can't remember exactly how the discussion of the
> needed-to-be-implemented interfaces was, so, from bugzilla I
> understand the next:
> 
> - GenericInterface
> - Processor
> - Camera
> - PortableMediaPlayer

Correct.

> And I don't know if I have to implement the next:
> 
> - AudioInterface
> - Video

Would be nice, but we hopefully can live without them. The Phonon people might 
hate us for releasing without support for those though.
 
> Some more comments on what I found a bit frustrating: I haven't got
> too many hardware here, so I can't really test what I have been doing,
> actually _right now_ here at home I have only Processor. My main
> problem has been also to map on what is what; to explain it further:
> what is exactly a Camera ? (I guess it is a Camera for taking photos,
> since a webcam should fall back to Video category),

Correct.

> and a
> PortableMediaPlayer ? (any MP3 can be considered a PortableMediaPlayer
> ?).

Correct.

> Now, more specific:
> 
> I still have to implement devicesFromQuery call of the UDev, since the
> parent stuff was rethought (as far as I understood on the sprint) I'd
> like to know if I really need to check some kind of tree (with real
> depth) or just check if I am being asked for the root or an element
> that is not root.

The latter shall be enough in your case.

> Icons and descriptions sure can be tweaked, and my question here is
> also: I have used queryDeviceInterface for not duplicating logic to
> detect certain types of devices, and I'd like to know if that is an
> accepted procedure to check this information.

Sounds good to me.

> Since I haven't got
> Camera or PortableMediaPlayers right now I just couldn't find out what
> HAL was returning in this case (the HAL backend most of the time just
> forwards what HAL returns) so I couldn't adapt it to the UDev backend.
> 
> Processors. I get them by asking driver == "processor", what I guess
> is fine. I get their "number of processor" just by analyzing the URI
> and stripping out the last number, what in UDev determines which CPU
> it is, starting by 0, as the solid documentation points out. Here I
> (or better said, we) have to do some kind of black magic to get the
> rest of the information of the processor, that is not provided by
> UDev. In the sprint we talked about directly parsing /proc/cpuinfo
> (yeah, it is kind of *hackish*), but we need to check out if there are
> other less dirty possible solutions.

It's hackish and fragile. I tested just now and I'm getting very mixed 
results, and different depending which computer I use. In all cases it doesn't 
see the throttling, on my laptop it reports maximum speed of 0 (oops!) and on 
my workstation the reported maximum speed seems to be the current running 
speed (it's a chaging value).

> I implemented hot plugging, but since I am only using "solid-hardware"
> helper, I can't really check it (anyways right now I filter out
> everything that is not a processor).

Since you can't hotplug processors you can't really test. ;-)

> How do you test hot plugging ? (I
> remember Kevin told me about a graphical application that lives in
> some branch at subversion, maybe it was that).

Yes, it is: branches/work/~ervin/solidhardwarebrowser

> So to wrap up:
> 
> - I am filtering everything except processors right now. I need to
> know how to filter the rest of the devices depending on what you tell
> me that it is needed to be implemented (see the top of this email).
> Probably I will have to filter: Processors, Cameras and
> PortableMediaPlayers.

Yes, please do that ASAP, that's critical to get the testing rolling. Even if 
some of the devices don't report useful info yet, that's fine.

> I think I can get a Camera (if Camera means a
> "Camera"), if not I will need some kind of help from someone that has
> one, and I also can check how to filter out PortableMediaPlayers if an
> MP3 is considered one (I have an MP3 at my cottage, which is very
> close from home). All this point basically affects
> UDevManager::Private::isOfInterest, that filters out the non
> interesting devices.
> 
> - Once I have this devices I can check what HAL returns for them, and
> I can just copy that behavior. I'd need someone with an iWHATEVER to
> help me out in how to detect that is _this_ kind of device.

It's supposed to be portable media player.
 
> - I also didn't know if when returning the root node I have to make
> the distinction between "computer" or "computer-laptop" on the icon.

Yes, not critical for 4.7 though.

Regards.
-- 
Kévin Ottens, http://ervin.ipsquad.net

KDAB - proud patron of KDE, http://www.kdab.com
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