On Thu, Jul 31, 2014 at 01:42:50PM +0200, Thierry Reding wrote: [...] > @@ -317,6 +319,12 @@ static int pwm_backlight_probe(struct platform_device *pdev) > } > > bl->props.brightness = data->dft_brightness; > + > + if (data->boot_off) > + bl->props.power = FB_BLANK_POWERDOWN; > + else > + bl->props.power = FB_BLANK_UNBLANK; > + > backlight_update_status(bl); Looking at this again, perhaps a more sensible thing to do would be to not call backlight_update_status() in the first place. For example if the board defines that backlight should be kept off at boot, but the bootloader had already enabled it, then this would effectively turn off the backlight again. I think it's safe to assume that if the bootloader sets up the backlight then it would also set up the display. Therefore not touching the backlight state at all at probe time seems like the safest default. Of course that doesn't help people who use some dumb framebuffer driver and therefore nothing explicitly enables the backlight. So it would still be changing behaviour for people for whom the bootloader doesn't set up the backlight at all and who therefore rely on the kernel to turn it on. We could perhaps alleviate that pain a little by making this dependent on whether or not the board is booted using DT on the assumption that anything that uses DT would be "modern" enough to provide a means to automatically enable the backlight at the right moment. Thierry
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