On Mon, 2007-02-26 at 16:24 +0100, Jiri Kosina wrote: > On Mon, 26 Feb 2007, Richard Purdie wrote: > > > Jiri: I've appended a patch that should already be queued, could you > > test and see if it solves the problem. > > Thanks. In the meantime I have gone through the code and I can confirm > that this is the root cause of what I am observing. > > Now regarding the patch - at the time when the dim happened previously, > currently there is a observable blink (after which the brightness is > correct).
The reason for the behaviour is that its turning the backlight down/off to save power as it thinks the screen is blank. The blink therefore makes sense as far as the backlight class is concerned and its working as intended now. > I have put some debugging printk() into fb_notifier_callback(), > and it turns out that on FB_EVENT_CONBLANK, there are two successive calls > to backlight_update_status(), second immediately following the first one: > > Feb 26 15:11:14 thunder kernel: calling backlight_update_status() with > bd->props.fb_blank == 1, bd->props.brightness == 0 > Feb 26 15:11:14 thunder kernel: calling backlight_update_status() with > bd->props.fb_blank == 0, bd->props.brightness == 0 > > Is this really a right thing to do? This should come from two calls to fbcon_generic_blank() in drivers/video/console/fbcon.c with a different blank parameter and is therefore in a way outside the scope of the backlight class. It would be interesting to know why it decides to blank then immediately unblank the display though. I've cc'd the fbdev-devel list. 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/
