[illumos-Developer] HAL

[Joerg Schilling]

Alan Coopersmith <alan.coopersmith at oracle.com> wrote:

> Owen Shepherd wrote:
> > Isn't Hal deprecated by it's author anyway? I'f my memory serves me
> > correctly then it should be a goal to move off Hal anyway.
>
> Yes, but they've only provided replacements for Linux systems, the
> udisks/upower/etc. series of extensions to the Linux udev framework.
> (DeviceKit was an interim step to those, but they killed DeviceKit
>  as well in favor of the u* interfaces, and churned through API's
>  in the process.)

Every such implementation on Linux did break cdrecord so far :-(

The reason is that we on Solaris have a correctly working state machine
inside the sd driver that is able to properly detect when a 

	no-media -> media

transition happened. On Linux all these implementations wake up on a

	not-ready -> ready

transition that e.g. happens when a CD writer in SAO mode signals a transition
from "ready with writing the leadin" -> "let us start with the data part".
Then these hostile implementations start to _read_ from the CD while it is 
written by cdrecord and kill the current BURN.

It seems that at least HALD and DeviceKit are from the same author and this
person does not reply to mail, so there is little hope that Linux will ever 
be fixed.



> Everyone else is on their own or stuck maintaining HAL.
>
> To remove HAL, you'd need to provide replacement interfaces for:
>  - removable media mounting (Tamarack, the vold replacement)
>  - GNOME interfaces for power management & disks
> and probably a few others I've forgotten.
>
> Moving Xorg on Solaris from HAL to libsysevent for input device
> hotplug notification and libdevinfo for input device discovery is
> on my long-term todo list, but again, for now HAL is required there.

Let us discuss this in order to avoid the problems known from Linux...

Jörg

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