Re: 2.6.21-rc1 dims my LCD

[Richard Purdie <rpurdie@rpsys.net>]

On Mon, 2007-02-26 at 13:03 -0300, Henrique de Moraes Holschuh wrote:
> On Mon, 26 Feb 2007, Jiri Kosina wrote:
> > Now regarding the patch - at the time when the dim happened previously, 
> > currently there is a observable blink (after which the brightness is 
> > correct). 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
> 
> This should cause *no* blink. It is setting brightness to zero anyway, which
> is all ibm-acpi cares about (without a patch I will be sending in soon).
> And ibm-acpi doesn't issue hardware calls that would not change the
> brightness value.

I'm assuming this was a paste from before your patch was applied and
that bd->props.brightness has a positive value when these calls were
made afterwards. Since the ibm backlight currently ignores fb_blank, it
shouldn't blink the backlight.

The screen still probably blinks since the framebuffer driver will see
the blank request too.

Richard