On Sat, 2010-04-03 at 10:35 +0200, Kay Sievers wrote:

On Sat, Apr 3, 2010 at 02:58, Ben Hutchings [off-list ref] wrote:

quoted

On Wed, 2010-03-31 at 07:51 +0200, Kay Sievers wrote:

quoted

Yeah, /sys/bus/, which is the only sane layout of the needlessly
different 3 versions of the same thing (bus, class, block).

[...]

block vs class/block is arguable,

That's already done long ago.

quoted

but as for abstracting the difference
between bus and class... why?

There is absolutely no need to needlessly export two versions of the
same thing. These directories serve no other purpose than to collect
all devices of the same subsystem. There is no useful information that
belongs to the type class or bus, they are both the same. Like
"inputX" is implemented as a class, but is much more like a bus.

Really, how do you enumerate 'input' buses?

And "usb" are devices, which are more a class of devices, and the
interfaces and contollers belong to a bus.

What common higher-level functionality do USB devices provide?

There is really no point to make userspace needlessly complicated to
distinguish the both.

We also have already a buch of subsystems which moved from class to
bus because they needed to express hierarchy between the same devices.
So the goal is to have only one type of subsystem to solve these
problems.

That's interesting.  Which were those?

[...]

quoted

So while buses and classes both define device interfaces, they are
fundamentally different types of interface.

No, they are not. They are just "devices". There is no useful
difference these two different types expose. And the class layout is
fundamentally broken, and not extendable. Peole mix lists of devices
with custom subsystem-wide attributes, which we need to stop from
doing this. The bus layout can carry custom directories, which is why
we want that by default for all "classifications".

[...]

I understand that you want to clean up a mess, but how do you know
you're not going to break user-space that depends on some of this mess?

Ben.

-- 
Ben Hutchings
Once a job is fouled up, anything done to improve it makes it worse.