Re: Backlight and LCD module patches [2]

From: Andrew Zabolotny (zap_at_homelink.ru)
Date: 07/30/04

  • Next message: Jon Smirl: "Re: Exposing ROM's though sysfs" 
    Date:	Sat, 31 Jul 2004 00:02:05 +0400
To: John Lenz <jelenz@students.wisc.edu>

    On Thu, 29 Jul 2004 19:49:50 -0500
    John Lenz <jelenz@students.wisc.edu> wrote:

    > The only problem is that what happens if the fb device is registered before
    > the lcd device? So that means you still need to keep around a list of fb
    > devices that have been registered so that when a new lcd device is
    > registered it can check if it matches an old fb device.
    Right now it happens in a different way. The patch I've published earlier uses
    notifier objects (linux/notifier.h) so that if framebuffer can't find the
    matched lcd device, it registers to be notified when new lcd devices appear in
    the system; when it does it proceeds like usual (e.g. calls lcd_device_find).
    Until it finds the LCD device framebuffer device cannot even initialize
    (without powering on the LCD controller in some circumstances it's impossible
    to do anything useful).

    > The only advantage is we let the core class code take care of managing the 2
    > lists of devices for us (which it is doing anyway).
    These lists are anyway maintained by the class.c core. You just need a pointer
    to the 'struct class' variable for classes you are interested in, and locking
    also comes for free - everything is already implemented. Look in class.c for
    list_for_each_entry macros - they all are traveling along these lists.

    I personally don't like to make this device matching too generalized - if we
    need it for b/l, that's fine, we'll have to implement it for b/l.
    But it doesn't look too sane, so I'd rather leave it l/b specific. 

    --
Greetings,
   Andrew
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  • Next message: Jon Smirl: "Re: Exposing ROM's though sysfs"