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Date:   Thu, 18 Jan 2018 12:02:10 +0000
From:   Daniel Thompson <daniel.thompson@linaro.org>
To:     Meghana Madhyastha <meghana.madhyastha@gmail.com>
Cc:     Noralf =?iso-8859-1?Q?Tr=F8nnes?= <noralf@tronnes.org>,
        Lee Jones <lee.jones@linaro.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>,
        Daniel Vetter <daniel.vetter@intel.com>,
        Sean Paul <seanpaul@chromium.org>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v16 01/10] video: backlight: Add helpers to enable and
 disable backlight
Message-ID: <20180118120210.7hyufn6r3776eggj@oak.lan>
References: <cover.1516098341.git.meghana.madhyastha@gmail.com>
 <0ef2305477e69efdf61a378079fb7404a40c909f.1516098341.git.meghana.madhyastha@gmail.com>
 <84821d63-edc4-9a9a-db54-a180bf5fe9f6@linaro.org>
 <7fe263d8-7b4a-68f1-2799-4b29d45dac89@tronnes.org>
 <20180118105922.GA4864@meghana-HP-Pavilion-Notebook>
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On Thu, Jan 18, 2018 at 04:29:23PM +0530, Meghana Madhyastha wrote:
> On Wed, Jan 17, 2018 at 11:03:24PM +0100, Noralf Tr?nnes wrote:
> > 
> > Den 17.01.2018 18.00, skrev Daniel Thompson:
> > >
> > >
> > >On 16/01/18 10:31, Meghana Madhyastha wrote:
> > >>Add helper functions backlight_enable and backlight_disable to
> > >>enable/disable a backlight device. These helper functions can
> > >>then be used by different drm and tinydrm drivers to avoid
> > >>repetition of code and also to enforce a uniform and consistent
> > >>way to enable/disable a backlight device.
> > >>
> > >>Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com>
> > >
> > >To be clear I don't disagree with anthing Daniel V. said about the
> > >horribly confused (and confusing) power states for backlight.
> > >
> > >Nevertheless I don't recall seeing any response (positive or negative) to
> > >this post from v13:
> > >https://www.spinics.net/lists/dri-devel/msg154459.html
> > >
> > 
> > I see that Daniel V has answered while I was chasing this down, but anyways:
> > 
> > A grep suggests that omap1_bl is the only driver that only checks fb_blank.
> > All the other drivers check both fb_blank and power, a few check state. The
> > backlight fbdev notifier callback doesn't set power, but sets fb_blank and
> > state.
> > 
> > fb_blank was marked 'Due to be removed' 9 years ago, so it hasn't been
> > high priority.
> > 
> > So for completeness I guess it makes sense to set fb_blank.
> 
> So if I understood correctly, the suggestion is to set fb_blank along
> with power i.e something like this in backlight_enable.
>         bd->props.power = FB_BLANK_UNBLANK;
> +       bd->props.fb_blank = FB_BLANK_UNBLANK;
>         bd->props.state &= ~BL_CORE_FBBLANK;
> 
> and set it to FB_BLANK_POWERDOWN in backlight_disable ?

Yes please.

Note that strictly speaking it is not "along with power" it is "along with
clearing the BL_CORE_FBBLANK bit" since that is what fb_blank must be
consistent with.


Daniel.

> 
> Thanks and regards,
> Meghana
> 
> > Noralf.
> > 
> > $ grep -r -C10 "props\.fb_blank" .
> > ./drivers/video/backlight/corgi_lcd.c-? if (bd->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/corgi_lcd.c-????????? intensity = 0;
> > ./drivers/video/backlight/corgi_lcd.c-
> > ./drivers/video/backlight/corgi_lcd.c:? if (bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/corgi_lcd.c-????????? intensity = 0;
> > --
> > ./drivers/video/backlight/adp8860_bl.c- if (bl->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/adp8860_bl.c-???????? brightness = 0;
> > ./drivers/video/backlight/adp8860_bl.c-
> > ./drivers/video/backlight/adp8860_bl.c: if (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/adp8860_bl.c-???????? brightness = 0;
> > --
> > ./drivers/video/backlight/hp680_bl.c-?? if (bd->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/hp680_bl.c-?????????? intensity = 0;
> > ./drivers/video/backlight/hp680_bl.c:?? if (bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/hp680_bl.c-?????????? intensity = 0;
> > --
> > ./drivers/video/backlight/cr_bllcd.c-static int
> > cr_backlight_set_intensity(struct backlight_device *bd)
> > ./drivers/video/backlight/cr_bllcd.c-{
> > ./drivers/video/backlight/cr_bllcd.c-?? int intensity =
> > bd->props.brightness;
> > ./drivers/video/backlight/cr_bllcd.c-?? u32 addr = gpio_bar +
> > CRVML_PANEL_PORT;
> > ./drivers/video/backlight/cr_bllcd.c-?? u32 cur = inl(addr);
> > ./drivers/video/backlight/cr_bllcd.c-
> > ./drivers/video/backlight/cr_bllcd.c-?? if (bd->props.power ==
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/cr_bllcd.c-?????????? intensity =
> > FB_BLANK_UNBLANK;
> > ./drivers/video/backlight/cr_bllcd.c:?? if (bd->props.fb_blank ==
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/cr_bllcd.c-?????????? intensity =
> > FB_BLANK_UNBLANK;
> > ./drivers/video/backlight/cr_bllcd.c-?? if (bd->props.power ==
> > FB_BLANK_POWERDOWN)
> > ./drivers/video/backlight/cr_bllcd.c-?????????? intensity =
> > FB_BLANK_POWERDOWN;
> > ./drivers/video/backlight/cr_bllcd.c:?? if (bd->props.fb_blank ==
> > FB_BLANK_POWERDOWN)
> > ./drivers/video/backlight/cr_bllcd.c-?????????? intensity =
> > FB_BLANK_POWERDOWN;
> > --
> > ./drivers/video/backlight/max8925_bl.c- if (bl->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/max8925_bl.c-???????? brightness = 0;
> > ./drivers/video/backlight/max8925_bl.c-
> > ./drivers/video/backlight/max8925_bl.c: if (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/max8925_bl.c-???????? brightness = 0;
> > ./drivers/video/backlight/max8925_bl.c-
> > ./drivers/video/backlight/max8925_bl.c- if (bl->props.state &
> > BL_CORE_SUSPENDED)
> > ./drivers/video/backlight/max8925_bl.c-???????? brightness = 0;
> > --
> > ./drivers/video/backlight/lv5207lp.c-?? if (backlight->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/lv5207lp.c: backlight->props.fb_blank !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/lv5207lp.c- backlight->props.state &
> > (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
> > ./drivers/video/backlight/lv5207lp.c-?????????? brightness = 0;
> > --
> > ./drivers/video/backlight/lm3533_bl.c-? if (bd->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/lm3533_bl.c-????????? brightness = 0;
> > ./drivers/video/backlight/lm3533_bl.c:? if (bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/lm3533_bl.c-????????? brightness = 0;
> > --
> > ./drivers/video/backlight/omap1_bl.c-static int omapbl_update_status(struct
> > backlight_device *dev)
> > ./drivers/video/backlight/omap1_bl.c-{
> > ./drivers/video/backlight/omap1_bl.c-?? struct omap_backlight *bl =
> > bl_get_data(dev);
> > ./drivers/video/backlight/omap1_bl.c-
> > ./drivers/video/backlight/omap1_bl.c-?? if (bl->current_intensity !=
> > dev->props.brightness) {
> > ./drivers/video/backlight/omap1_bl.c-?????????? if (bl->powermode ==
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/omap1_bl.c-
> > omapbl_send_intensity(dev->props.brightness);
> > ./drivers/video/backlight/omap1_bl.c- bl->current_intensity =
> > dev->props.brightness;
> > ./drivers/video/backlight/omap1_bl.c-?? }
> > ./drivers/video/backlight/omap1_bl.c-
> > ./drivers/video/backlight/omap1_bl.c:?? if (dev->props.fb_blank !=
> > bl->powermode)
> > ./drivers/video/backlight/omap1_bl.c: omapbl_set_power(dev,
> > dev->props.fb_blank);
> > ./drivers/video/backlight/omap1_bl.c-
> > ./drivers/video/backlight/omap1_bl.c-?? return 0;
> > ./drivers/video/backlight/omap1_bl.c-}
> > ./drivers/video/backlight/omap1_bl.c-
> > --
> > ./drivers/video/backlight/kb3886_bl.c-? if (bd->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/kb3886_bl.c-????????? intensity = 0;
> > ./drivers/video/backlight/kb3886_bl.c:? if (bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/kb3886_bl.c-????????? intensity = 0;
> > --
> > ./drivers/video/backlight/pwm_bl.c-???? if (bl->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/pwm_bl.c:???????? bl->props.fb_blank !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/pwm_bl.c-???????? bl->props.state &
> > BL_CORE_FBBLANK)
> > ./drivers/video/backlight/pwm_bl.c-???????????? brightness = 0;
> > --
> > ./drivers/video/backlight/pm8941-wled.c-??????? if (bl->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/pm8941-wled.c: bl->props.fb_blank !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/pm8941-wled.c- bl->props.state & BL_CORE_FBBLANK)
> > ./drivers/video/backlight/pm8941-wled.c-??????????????? val = 0;
> > --
> > ./drivers/video/backlight/adp8870_bl.c- if (bl->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/adp8870_bl.c-???????? brightness = 0;
> > ./drivers/video/backlight/adp8870_bl.c-
> > ./drivers/video/backlight/adp8870_bl.c: if (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/adp8870_bl.c-???????? brightness = 0;
> > --
> > ./drivers/video/backlight/as3711_bl.c-? if (bl->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/as3711_bl.c:????? bl->props.fb_blank !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/as3711_bl.c-????? bl->props.state &
> > (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
> > ./drivers/video/backlight/as3711_bl.c-????????? brightness = 0;
> > --
> > ./drivers/video/backlight/88pm860x_bl.c-??????? if (bl->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/88pm860x_bl.c-??????????????? brightness = 0;
> > ./drivers/video/backlight/88pm860x_bl.c-
> > ./drivers/video/backlight/88pm860x_bl.c:??????? if (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/88pm860x_bl.c-??????????????? brightness = 0;
> > ./drivers/video/backlight/88pm860x_bl.c-
> > ./drivers/video/backlight/88pm860x_bl.c-??????? if (bl->props.state &
> > BL_CORE_SUSPENDED)
> > ./drivers/video/backlight/88pm860x_bl.c-??????????????? brightness = 0;
> > --
> > ./drivers/video/backlight/tps65217_bl.c-??????? if (bl->props.state &
> > BL_CORE_SUSPENDED)
> > ./drivers/video/backlight/tps65217_bl.c-??????????????? brightness = 0;
> > ./drivers/video/backlight/tps65217_bl.c-
> > ./drivers/video/backlight/tps65217_bl.c-??????? if ((bl->props.power !=
> > FB_BLANK_UNBLANK) ||
> > ./drivers/video/backlight/tps65217_bl.c: (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK))
> > ./drivers/video/backlight/tps65217_bl.c-??????????????? /* framebuffer in
> > low power mode or blanking active */
> > ./drivers/video/backlight/tps65217_bl.c-??????????????? brightness = 0;
> > --
> > ./drivers/video/backlight/adp5520_bl.c- if (bl->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/adp5520_bl.c-???????? brightness = 0;
> > ./drivers/video/backlight/adp5520_bl.c-
> > ./drivers/video/backlight/adp5520_bl.c: if (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/adp5520_bl.c-???????? brightness = 0;
> > --
> > ./drivers/video/backlight/wm831x_bl.c-? if (bl->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/wm831x_bl.c-????????? brightness = 0;
> > ./drivers/video/backlight/wm831x_bl.c-
> > ./drivers/video/backlight/wm831x_bl.c:? if (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/wm831x_bl.c-????????? brightness = 0;
> > ./drivers/video/backlight/wm831x_bl.c-
> > ./drivers/video/backlight/wm831x_bl.c-? if (bl->props.state &
> > BL_CORE_SUSPENDED)
> > ./drivers/video/backlight/wm831x_bl.c-????????? brightness = 0;
> > --
> > ./drivers/video/backlight/gpio_backlight.c-???? if (bl->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/gpio_backlight.c: bl->props.fb_blank !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/gpio_backlight.c- bl->props.state &
> > (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
> > ./drivers/video/backlight/gpio_backlight.c-???????????? brightness = 0;
> > --
> > ./drivers/video/backlight/da903x_bl.c-? if (bl->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/da903x_bl.c-????????? brightness = 0;
> > ./drivers/video/backlight/da903x_bl.c-
> > ./drivers/video/backlight/da903x_bl.c:? if (bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/da903x_bl.c-????????? brightness = 0;
> > ./drivers/video/backlight/da903x_bl.c-
> > ./drivers/video/backlight/da903x_bl.c-? if (bl->props.state &
> > BL_CORE_SUSPENDED)
> > ./drivers/video/backlight/da903x_bl.c-????????? brightness = 0;
> > --
> > ./drivers/video/backlight/locomolcd.c-? if (bd->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/locomolcd.c-????????? intensity = 0;
> > ./drivers/video/backlight/locomolcd.c:? if (bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/locomolcd.c-????????? intensity = 0;
> > --
> > ./drivers/video/backlight/bd6107.c-???? if (backlight->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/bd6107.c: backlight->props.fb_blank !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/bd6107.c- backlight->props.state &
> > (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
> > ./drivers/video/backlight/bd6107.c-???????????? brightness = 0;
> > --
> > ./drivers/video/backlight/backlight.c-????????????????? if (fb_blank ==
> > FB_BLANK_UNBLANK &&
> > ./drivers/video/backlight/backlight.c- !bd->fb_bl_on[node]) {
> > ./drivers/video/backlight/backlight.c- bd->fb_bl_on[node] = true;
> > ./drivers/video/backlight/backlight.c-????????????????????????? if
> > (!bd->use_count++) {
> > ./drivers/video/backlight/backlight.c- bd->props.state &= ~BL_CORE_FBBLANK;
> > ./drivers/video/backlight/backlight.c: bd->props.fb_blank =
> > FB_BLANK_UNBLANK;
> > ./drivers/video/backlight/backlight.c- backlight_update_status(bd);
> > ./drivers/video/backlight/backlight.c-????????????????????????? }
> > ./drivers/video/backlight/backlight.c-????????????????? } else if (fb_blank
> > != FB_BLANK_UNBLANK &&
> > ./drivers/video/backlight/backlight.c- bd->fb_bl_on[node]) {
> > ./drivers/video/backlight/backlight.c- bd->fb_bl_on[node] = false;
> > ./drivers/video/backlight/backlight.c-????????????????????????? if
> > (!(--bd->use_count)) {
> > ./drivers/video/backlight/backlight.c- bd->props.state |= BL_CORE_FBBLANK;
> > ./drivers/video/backlight/backlight.c: bd->props.fb_blank = fb_blank;
> > ./drivers/video/backlight/backlight.c- backlight_update_status(bd);
> > --
> > ./drivers/video/backlight/ep93xx_bl.c-? if (bl->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/backlight/ep93xx_bl.c:????? bl->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/backlight/ep93xx_bl.c-????????? brightness = 0;
> > --
> > ./drivers/video/backlight/jornada720_bl.c:????? if ((bd->props.power !=
> > FB_BLANK_UNBLANK) || (bd->props.fb_blank != FB_BLANK_UNBLANK)) {
> > --
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-dsi-cm.c:???? if
> > (dev->props.fb_blank == FB_BLANK_UNBLANK &&
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-dsi-cm.c- dev->props.power
> > == FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-dsi-cm.c- level =
> > dev->props.brightness;
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-dsi-cm.c-???? else
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-dsi-cm.c- level = 0;
> > --
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c: if
> > (dev->props.fb_blank == FB_BLANK_UNBLANK &&
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c-
> > dev->props.power == FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c- level =
> > dev->props.brightness;
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c- else
> > ./drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c- level =
> > 0;
> > --
> > ./drivers/video/fbdev/aty/atyfb_base.c- if (bd->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/fbdev/aty/atyfb_base.c:???? bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/aty/atyfb_base.c-???????? level = 0;
> > ./drivers/video/fbdev/aty/atyfb_base.c- else
> > ./drivers/video/fbdev/aty/atyfb_base.c-???????? level =
> > bd->props.brightness;
> > --
> > ./drivers/video/fbdev/aty/aty128fb.c-?? if (bd->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/fbdev/aty/aty128fb.c:?????? bd->props.fb_blank !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/fbdev/aty/aty128fb.c-?????? !par->lcd_on)
> > ./drivers/video/fbdev/aty/aty128fb.c-?????????? level = 0;
> > ./drivers/video/fbdev/aty/aty128fb.c-?? else
> > ./drivers/video/fbdev/aty/aty128fb.c-?????????? level =
> > bd->props.brightness;
> > --
> > ./drivers/video/fbdev/aty/radeon_backlight.c-??????? if (bd->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/fbdev/aty/radeon_backlight.c: bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/aty/radeon_backlight.c-?????????? level = 0;
> > ./drivers/video/fbdev/aty/radeon_backlight.c-?? else
> > ./drivers/video/fbdev/aty/radeon_backlight.c-?????????? level =
> > bd->props.brightness;
> > --
> > ./drivers/video/fbdev/mx3fb.c-? if (bl->props.power != FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/mx3fb.c-????????? brightness = 0;
> > ./drivers/video/fbdev/mx3fb.c:? if (bl->props.fb_blank != FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/mx3fb.c-????????? brightness = 0;
> > --
> > ./drivers/video/fbdev/riva/fbdev.c-???? if (bd->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/fbdev/riva/fbdev.c:???????? bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/riva/fbdev.c-???????????? level = 0;
> > ./drivers/video/fbdev/riva/fbdev.c-???? else
> > ./drivers/video/fbdev/riva/fbdev.c-???????????? level =
> > bd->props.brightness;
> > --
> > ./drivers/video/fbdev/atmel_lcdfb.c:??? if (bl->props.fb_blank !=
> > sinfo->bl_power)
> > ./drivers/video/fbdev/atmel_lcdfb.c:??????????? power = bl->props.fb_blank;
> > ./drivers/video/fbdev/atmel_lcdfb.c-??? else if (bl->props.power !=
> > sinfo->bl_power)
> > ./drivers/video/fbdev/atmel_lcdfb.c-??????????? power = bl->props.power;
> > --
> > ./drivers/video/fbdev/nvidia/nv_backlight.c-??? if (bd->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/video/fbdev/nvidia/nv_backlight.c: bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/video/fbdev/nvidia/nv_backlight.c-??????????? level = 0;
> > ./drivers/video/fbdev/nvidia/nv_backlight.c-??? else
> > ./drivers/video/fbdev/nvidia/nv_backlight.c-??????????? level =
> > bd->props.brightness;
> > --
> > ./drivers/macintosh/via-pmu-backlight.c-??????? if (bd->props.power !=
> > FB_BLANK_UNBLANK ||
> > ./drivers/macintosh/via-pmu-backlight.c: bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/macintosh/via-pmu-backlight.c-??????????????? level = 0;
> > --
> > ./drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c:????? if
> > (dev->props.fb_blank == FB_BLANK_UNBLANK &&
> > ./drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c- dev->props.power ==
> > FB_BLANK_UNBLANK)
> > ./drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c- level =
> > dev->props.brightness;
> > ./drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c-????? else
> > ./drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c- level = 0;
> > --
> > ./drivers/gpu/drm/omapdrm/displays/panel-sony-acx565akm.c:????? if
> > (dev->props.fb_blank == FB_BLANK_UNBLANK &&
> > ./drivers/gpu/drm/omapdrm/displays/panel-sony-acx565akm.c- dev->props.power
> > == FB_BLANK_UNBLANK)
> > ./drivers/gpu/drm/omapdrm/displays/panel-sony-acx565akm.c- level =
> > dev->props.brightness;
> > ./drivers/gpu/drm/omapdrm/displays/panel-sony-acx565akm.c-????? else
> > ./drivers/gpu/drm/omapdrm/displays/panel-sony-acx565akm.c- level = 0;
> > --
> > ./drivers/staging/fbtft/fb_ssd1351.c-?? on = (bd->props.power ==
> > FB_BLANK_UNBLANK) &&
> > ./drivers/staging/fbtft/fb_ssd1351.c:??????? (bd->props.fb_blank ==
> > FB_BLANK_UNBLANK);
> > --
> > ./drivers/staging/fbtft/fbtft-core.c-?? if ((bd->props.power ==
> > FB_BLANK_UNBLANK) &&
> > ./drivers/staging/fbtft/fbtft-core.c:?????? (bd->props.fb_blank ==
> > FB_BLANK_UNBLANK))
> > --
> > ./drivers/staging/fbtft/fb_watterott.c- if (bd->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/staging/fbtft/fb_watterott.c-???????? brightness = 0;
> > ./drivers/staging/fbtft/fb_watterott.c-
> > ./drivers/staging/fbtft/fb_watterott.c: if (bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/staging/fbtft/fb_watterott.c-???????? brightness = 0;
> > --
> > ./drivers/auxdisplay/ht16k33.c- if (bl->props.power != FB_BLANK_UNBLANK ||
> > ./drivers/auxdisplay/ht16k33.c:???? bl->props.fb_blank != FB_BLANK_UNBLANK
> > ||
> > ./drivers/auxdisplay/ht16k33.c-???? bl->props.state & BL_CORE_FBBLANK ||
> > brightness == 0) {
> > ./drivers/auxdisplay/ht16k33.c-???????? return ht16k33_display_off(priv);
> > --
> > ./drivers/platform/x86/thinkpad_acpi.c: (bd->props.fb_blank ==
> > FB_BLANK_UNBLANK &&
> > ./drivers/platform/x86/thinkpad_acpi.c-????????? bd->props.power ==
> > FB_BLANK_UNBLANK) ?
> > ./drivers/platform/x86/thinkpad_acpi.c- bd->props.brightness : 0;
> > --
> > ./drivers/platform/x86/acer-wmi.c-????? if (bd->props.power !=
> > FB_BLANK_UNBLANK)
> > ./drivers/platform/x86/acer-wmi.c-????????????? intensity = 0;
> > ./drivers/platform/x86/acer-wmi.c:????? if (bd->props.fb_blank !=
> > FB_BLANK_UNBLANK)
> > ./drivers/platform/x86/acer-wmi.c-????????????? intensity = 0;
> > 
> > >
> > >Daniel.
> > >
> > >
> > >>---
> > >>? include/linux/backlight.h | 30 ++++++++++++++++++++++++++++++
> > >>? 1 file changed, 30 insertions(+)
> > >>
> > >>diff --git a/include/linux/backlight.h b/include/linux/backlight.h
> > >>index af7003548..7b6a9a2a3 100644
> > >>--- a/include/linux/backlight.h
> > >>+++ b/include/linux/backlight.h
> > >>@@ -130,6 +130,36 @@ static inline int backlight_update_status(struct
> > >>backlight_device *bd)
> > >>????? return ret;
> > >>? }
> > >>? +/**
> > >>+? * backlight_enable - Enable backlight
> > >>+? * @bd: the backlight device to enable
> > >>+? */
> > >>+static inline int backlight_enable(struct backlight_device *bd)
> > >>+{
> > >>+??? if (!bd)
> > >>+??????? return 0;
> > >>+
> > >>+??? bd->props.power = FB_BLANK_UNBLANK;
> > >>+??? bd->props.state &= ~BL_CORE_FBBLANK;
> > >>+
> > >>+??? return backlight_update_status(bd);
> > >>+}
> > >>+
> > >>+/**
> > >>+? * backlight_disable - Disable backlight
> > >>+? * @bd: the backlight device to disable
> > >>+? */
> > >>+static inline int backlight_disable(struct backlight_device *bd)
> > >>+{
> > >>+??? if (!bd)
> > >>+??????? return 0;
> > >>+
> > >>+??? bd->props.power = FB_BLANK_POWERDOWN;
> > >>+??? bd->props.state |= BL_CORE_FBBLANK;
> > >>+
> > >>+??? return backlight_update_status(bd);
> > >>+}
> > >>+
> > >>? extern struct backlight_device *backlight_device_register(const char
> > >>*name,
> > >>????? struct device *dev, void *devdata, const struct backlight_ops
> > >>*ops,
> > >>????? const struct backlight_properties *props);
> > >>
> >