Hi Greg, On Thu, 2007-02-08 at 13:23 -0800, Greg KH wrote: > On Thu, Feb 08, 2007 at 06:32:02PM +0000, James Simmons wrote: > > I CC Greg to explain. The backlight class didn't go away. The way it is > > handled is different. > > Have a pointer to the patch so I can help explain better?
You've been cc'd on the proposed patch a couple of times in this thread so it should be in your mailbox now. > As a short summary, 'struct class_device' is going away. Using a > 'struct device' in its place is what the conversion should have just > done, no functionality change otherwise. The backlight class is drivers/video/backlight/backlight.c and if I understand things correctly what shows up in sysfs changes. At the moment (as I understand the code which could be wrong), the backlight functionality is tagged onto an existing device. Taking drivers/video/backlight/corgi_bl.c as an example, the corgi_bl device exists under /sys/devices/platform/corgi_bl with an associated struct device. The backlight code then appends some magic to this to link in some class attributes that show up under /sys/class/backlight. There is only ever one device. By replacing class_device_register() with device_create(), the proposed patch appears to generate a second struct device with the original as its parent. I'm not sure where it appears in /sys/devices? Having another full blown struct device around makes me uneasy as wherever it appears, we only have one device, not two. If I had some kind of platform device which had an LED, backlight and say battery component and registered with the three appropriate classes would that mean four struct devices? Where under /sys/devices do they each appear? Also, it was mentioned that a parent struct device is a requirement and this isn't the case for all backlight users. I think this constraint on device_create has been removed in more recent code though? Richard - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
