Re: [Hdaps-devel] [PATCH 2.6.23-rc2] hwmon: HP Mobile Data ProtectionSystem 3D ACPI driver (resend)

[Yan Burman]

Henrique de Moraes Holschuh wrote:
> On Thu, 30 Aug 2007, Yan Burman wrote:
>   
> > > > You can generate events on input devices, but I am not sure that's the
> > > > best way to go about it for this.  Things that block on read until an
> > > > interrupt happens might work better.
> > > >         
> > > You can do the latter via another (4th) input device.
> > >
> > >       
> > What's wrong with the stuff I did in mdps? a misc character device that
> > acts like /dev/rtc. Why does it have to be input device oriented?
> >     
>
> I am fine with a char device that acts like /dev/rtc, but if we are doing
> something as heavyweight as a char device, I'd rather we go full generic
> netlink and send the various events over it.  We'd have a netlink device
> that sends everything over various "channels" and just one input device that
> does joystick emulation, then.
>
> Can we use a simple sysfs attribute that blocks the caller on write and
> returns immediately on read? If it has to be more complicated than that, I'd
> rather we go the netlink path. Any other ideas that are not a char device,
> not a netlink socket, not an input device node, and not a sysfs attribute?
>
>   
But, how are you going to make the sysfs attribute look generic so that 
application will not have to know whether to go
to /sys/.../mdps /sys/.../hdaps/ or /sys/.../whatever?

I'd probably prefer netlink, since this way it's something more generic 
and if some more functionality is added, you don't need to start
adding more sysfs attributes.

Sorry it took me a while to respond - I was too busy lately.

> > I also looked at what you did in the patches as well as the modified 
> > hdapsd. I'm doing the raw input device right now in the mdps, but I have a 
> > suggestion.
> >
> > It seems to me that right now there are at least 3 drivers that provide the 
> > same functionality - hdaps, ams and mdps. Why not create the input device
> > that exports raw accelerometer data with a name that is generic - something 
> > like accel/input or something along those lines. This way hdapsd could work
> > with any driver that provides the functionality without being hdaps 
> > specific.
> >     
>
> THAT is the idea, IMO.  But the naming is userspace's problem (thorugh
> udev), not ours :-)
>
> Or do you mean the "hardware port" part of the input device? If so, yes, we
> should try to make standard names for those as that makes it easier for
> userspace.
>
>   

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