linux-kernel - Re: 2.6.21-rc1 dims my LCD

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 26 Feb 2007 17:01:11 +0000
From:	Richard Purdie <rpurdie@...ys.net>
To:	Henrique de Moraes Holschuh <hmh@....eng.br>
Cc:	Jiri Kosina <jikos@...os.cz>, linux-kernel@...r.kernel.org
Subject: Re: 2.6.21-rc1 dims my LCD

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

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