Re: [PATCH] resend: radeon backlight shutoff flashes momentarily

["Michel Dänzer" <michel@daenzer.net>]

On Wed, 2009-04-01 at 13:21 +0200, Michel Dänzer wrote:
> On Wed, 2009-04-01 at 02:27 -0700, Robert T. Drury wrote:
> > Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12845
> > 
> > Aluminum Powerbook G4 with Radeon 9600:
> > 
> > The backlight momentarily flashes brightly when turning off.  If the
> > backlight is originally dim, the flash is more noticeable.  This momentary
> > flash is stressful on the power circuit.
> > 
> > This patch removes the & ~LVDS_BL_MOD_EN above the first OUTREG to 
> > LVDS_GEN_CNTL to eliminate the flash on shutoff, only for powerbook5,3 
> > and CHIP_FAMILY_RV350.
> 
> As you're checking for a specific Apple laptop model, there's no need to
> check the chip family as well.
> 
> (As mentioned before, I'm seeing the flash on a PowerBook5,8 as well,
> but I haven't got around to trying the patch, will do when I get time)

Unfortunately, 2.6.29.1 with the patch below doesn't seem to get rid of
the flash on my PowerBook5,8. So no objections to your patch from me.


diff --git a/drivers/video/aty/radeon_backlight.c b/drivers/video/aty/radeon_backlight.c
index 1a056ad..361bb64 100644
--- a/drivers/video/aty/radeon_backlight.c
+++ b/drivers/video/aty/radeon_backlight.c
@@ -101,7 +101,10 @@ static int radeon_bl_update_status(struct backlight_device *bd)
 		tmpPixclksCntl = INPLL(PIXCLKS_CNTL);
 		if (rinfo->is_mobility || rinfo->is_IGP)
 			OUTPLLP(PIXCLKS_CNTL, 0, ~PIXCLK_LVDS_ALWAYS_ONb);
-		lvds_gen_cntl &= ~(LVDS_BL_MOD_LEVEL_MASK | LVDS_BL_MOD_EN);
+		lvds_gen_cntl &= ~LVDS_BL_MOD_LEVEL_MASK;
+		if (!(machine_is_compatible("PowerBook5,3") ||
+		      machine_is_compatible("PowerBook5,8")))
+			lvds_gen_cntl &= ~LVDS_BL_MOD_EN;
 		lvds_gen_cntl |= (radeon_bl_get_level_brightness(pdata, 0) <<
 				  LVDS_BL_MOD_LEVEL_SHIFT);
 		lvds_gen_cntl |= LVDS_DISPLAY_DIS;


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer

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