On 16:13 Thu 30 May , Liu Ying wrote: > We don't have to turn backlight on/off everytime a blanking > or unblanking event comes because the backlight status may have > already been what we want. Another thought is that one backlight > device may be shared by multiple framebuffers. We don't hope that > blanking one of the framebuffers would turn the backlight off for > all the other framebuffers, since they are likely active to show > display content. This patch adds logic to record each framebuffer's > backlight status to determine the backlight device use count and > whether the backlight should be turned on or off. > > Signed-off-by: Liu Ying <[email protected]> > --- > drivers/video/backlight/backlight.c | 23 +++++++++++++++++------ > include/linux/backlight.h | 6 ++++++ > 2 files changed, 23 insertions(+), 6 deletions(-) > > diff --git a/drivers/video/backlight/backlight.c > b/drivers/video/backlight/backlight.c > index c74e7aa..97ea2b8 100644 > --- a/drivers/video/backlight/backlight.c > +++ b/drivers/video/backlight/backlight.c > @@ -31,13 +31,14 @@ static const char *const backlight_types[] = { > defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) > /* This callback gets called when something important happens inside a > * framebuffer driver. We're looking if that important event is blanking, > - * and if it is, we're switching backlight power as well ... > + * and if it is and necessary, we're switching backlight power as well ... > */ > static int fb_notifier_callback(struct notifier_block *self, > unsigned long event, void *data) > { > struct backlight_device *bd; > struct fb_event *evdata = data; > + int node = evdata->info->node; > > /* If we aren't interested in this event, skip it immediately ... */ > if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK) > @@ -49,11 +50,21 @@ static int fb_notifier_callback(struct notifier_block > *self, > if (!bd->ops->check_fb || > bd->ops->check_fb(bd, evdata->info)) { > bd->props.fb_blank = *(int *)evdata->data; > - if (bd->props.fb_blank == FB_BLANK_UNBLANK) > - bd->props.state &= ~BL_CORE_FBBLANK; > - else > - bd->props.state |= BL_CORE_FBBLANK; > - backlight_update_status(bd); > + if (bd->props.fb_blank == FB_BLANK_UNBLANK && > + !bd->fb_bl_on[node]) { > + bd->fb_bl_on[node] = true; > + if (!bd->use_count++) { > + bd->props.state &= ~BL_CORE_FBBLANK; > + backlight_update_status(bd); > + } > + } else if (bd->props.fb_blank != FB_BLANK_UNBLANK && > + bd->fb_bl_on[node]) { > + bd->fb_bl_on[node] = false; > + if (!(--bd->use_count)) { > + bd->props.state |= BL_CORE_FBBLANK; > + backlight_update_status(bd); > + } > + } > } > mutex_unlock(&bd->ops_lock); > return 0; > diff --git a/include/linux/backlight.h b/include/linux/backlight.h > index da9a082..5de71a0 100644 > --- a/include/linux/backlight.h > +++ b/include/linux/backlight.h > @@ -9,6 +9,7 @@ > #define _LINUX_BACKLIGHT_H > > #include <linux/device.h> > +#include <linux/fb.h> > #include <linux/mutex.h> > #include <linux/notifier.h> > > @@ -101,6 +102,11 @@ struct backlight_device { > struct notifier_block fb_notif; > > struct device dev; > + > + /* Multiple framebuffers may share one backlight device */ > + bool fb_bl_on[FB_MAX];
I don't like such array at all I understand the fact you will have only on hw backlight for x fb or overlay but have a static on no if you want to track all user create a strcut and register it or do more simple just as a int to count the number of user and shut down it if 0 and enable it otherwise Best Regards, J. > + > + int use_count; > }; > > static inline void backlight_update_status(struct backlight_device *bd) > -- > 1.7.1 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
