linux-kernel - Re: [PATCH] drm/kms: fix fbdev blanking regression

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Message-ID: <alpine.LFD.2.00.1001061814360.5372@casper.infradead.org>
Date:	Wed, 6 Jan 2010 18:18:41 +0000 (GMT)
From:	James Simmons <jsimmons@...radead.org>
To:	Johan Hovold <jhovold@...il.com>
cc:	Dave Airlie <airlied@...hat.com>, dri-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/kms: fix fbdev blanking regression


> > > Commit 731b5a15a3b1474a41c2ca29b4c32b0f21bc852e (drm/kms: properly
> > > handle fbdev blanking) breaks console blanking on my laptop (GM45
> > > chipset). Instead of blanking the screen, it is dimmed and then the
> > > backlight starts "glowing" in the lower edges of the screen. The glowing
> > > then slowly spreads upwards. Does not look healthy at all...
> > > 
> > > This patch reverts to the old behaviour of going directly to
> > > DPMS_STANDBY.
> > 
> > The current fbdev blank is correct. Normal blanking doesn't power down 
> > the hsync or the vsync signals. If you look at fbdev drivers you will see 
> > this type of behavior. If you want a full power down then a FB_BLANK_POWERDOWN 
> > is needed. As for the blacklight that is a another problem not related to 
> > this issue. The fbdev layer sends a event to the backlight layer to tell 
> > it to power down. That powerdown happens for the backlight in all cases 
> > except FB_BLANK_UNBLANK. How is your backlight setup. Is the backlight 
> > handled via the DRI driver or acpi?
> > 
> 
> The change itself looks correct but it triggers something that seems to
> hurt my screen bad. :)

Yeap. The fix uncovered a bug in your driver. I haven't heard of problems 
with the other drm drivers.
 
> The backlight is handled via the DRI driver I assume. At least
> i9xx_crtc_dpms is called on powerdown.

Can you post your dmesg and kernel config.

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