On Wednesday, January 22, 2014 6:36 PM, Jani Nikula wrote: > On Mon, 20 Jan 2014, Liu Ying <Ying.Liu@xxxxxxxxxxxxx> 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 blanking one of the framebuffers may turn the > > backlight off for all the other framebuffers, since they are > > likely being active to display something. This patch adds > > some logics to record each framebuffer's backlight usage to > > determine the backlight device use count and whether the > > backlight should be turned on or off. To be more specific, > > only one unblank operation on a certain blanked framebuffer > > may increase the backlight device's use count by one, while > > one blank operation on a certain unblanked framebuffer may > > decrease the use count by one, because the userspace is > > likely to unblank a unblanked framebuffer or blank a blanked > > framebuffer. > > > > Signed-off-by: Liu Ying <Ying.Liu@xxxxxxxxxxxxx> > > --- > > v1 can be found at https://lkml.org/lkml/2013/5/30/139 > > > > v1->v2: > > * Make the commit message be more specific about the condition > > in which backlight device use count can be increased/decreased. > > * Correct the setting for bd->props.fb_blank. > > > > drivers/video/backlight/backlight.c | 28 +++++++++++++++++++++------- > > include/linux/backlight.h | 6 ++++++ > > 2 files changed, 27 insertions(+), 7 deletions(-) > > [.....] > > Anything backlight worries me a little, and there are actually three > changes bundled into one patch here: > > 1. Changing bd->props.state and bd->props.fb_blank only when use_count > changes from 0->1 or 1->0. > > 2. Calling backlight_update_status() only with the above change, and not > on all notifier callbacks. > > 3. Setting bd->props.fb_blank always to either FB_BLANK_UNBLANK or > FB_BLANK_POWERDOWN instead of *(int *)evdata->data. > > The rationale in the commit message seems plausible, and AFAICT the code > does what it says on the box, so for that (and for that alone) you can > have my > > Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx> > > *BUT* it would be laborous to figure out whether this change in > behaviour might regress some drivers. I'm just punting on that. And that > brings us back to the three changes above - in a bisect POV it might be > helpful to split the patch up. Up to the maintainers. I agree with Jani Nikula's opinion. Please split this patch into three patches as above mentioned. Best regards, Jingoo Han _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
