lkml.org 
[lkml]   [2005]   [Oct]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch 0/8] Nesting class_device patches that actually work
    On Fri, Oct 14, 2005 at 10:45:54AM +0200, Kay Sievers wrote:

    > Sure, than that physical (while that distinction is silly by itself)
    > will just have several child devices. Look at the mouse0 and event0 in
    > the ascii drawing.
    >
    > That solution would keep a better device separation, sure. But it is
    > completely incompatible with everything we ever had in sysfs and
    > nobody wants to rewrite _all_ userspace programs.
    >
    > It invents artificial subclass names below a "master" class, which is
    > absolutely not needed.
    >
    > It creates the magic "interfaces" directory, which is confusing, cause
    > it classifies devices by itself.
    >
    > It doesn't represent any relationship and hierarchy of devices and
    > adding a forest of magic symlinks and "device" pointers is a very bad
    > design. The proposed "inter-class" symlinks make it even harder to
    > understand sysfs as it already is.
    >
    > The biggest problem with current sysfs is that the driver hacker has
    > to decide if the device is "hardware" or "virtual" which in a lot of
    > cases just can't tell and this distiction doesn't make any sense
    > today.
    >
    > All the more complex subsystems use "virtual buses" and an unconnected
    > bunch of class-devices to model its sysfs represention, which is just
    > to work around a major design flaw in sysfs! We really should get
    > _one_ device tree with its natural hierarchy, get rid of the stupid
    > "device"-link, the PHYSDEVPATH and the unconnected class devices.
    > Every device should just carry its dependency tree in it _own_
    > devpath!
    >
    > I'm very sure, we want a unified tree in /sys/devices, regardless of
    > the type of device, to represent the global hierarchy wich is exactly
    > what you want to know from a device tree! That way we stack "virtual"
    > _and_ "physical" in a sane manner and at the same time get very clean
    > class interfaces. We would stop to mix up "hierarchy" and "classes"
    > all over the tree.

    Let me just say: I completely agree here. The hard distinction between
    'real' and 'virtual' devices causes more problems than it solves.

    --
    Vojtech Pavlik
    SuSE Labs, SuSE CR
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-10-17 11:30    [W:4.090 / U:0.064 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site