On Tue, 07 Oct 2014, Thierry Reding wrote: > On Mon, Oct 06, 2014 at 09:22:44PM +0200, Markus Pargmann wrote: > > The backlight will be enabled by the panel again if it is used. So we > > can save the default brightness and disable the pwm backlight when > > probing. > > > > Signed-off-by: Markus Pargmann <[email protected]> > > --- > > drivers/video/backlight/pwm_bl.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/video/backlight/pwm_bl.c > > b/drivers/video/backlight/pwm_bl.c > > index 336b83be7e2d..b4f433a6f106 100644 > > --- a/drivers/video/backlight/pwm_bl.c > > +++ b/drivers/video/backlight/pwm_bl.c > > @@ -317,9 +317,11 @@ static int pwm_backlight_probe(struct platform_device > > *pdev) > > data->dft_brightness = data->max_brightness; > > } > > > > - bl->props.brightness = data->dft_brightness; > > + bl->props.brightness = 0; > > backlight_update_status(bl); > > > > + bl->props.brightness = data->dft_brightness; > > + > > platform_set_drvdata(pdev, bl); > > return 0; > > > > It would be nice if it was that easy. But we can't do this, because it > will regress for users of this driver that don't use a panel or DRM. If > the PWM backlight driver is used for example in conjunction with a plain > fbdev driver it isn't necessarily hooked up with anything and won't be > enabled automatically. That's really bad if fbdev is the only output you > have since you'd have to blindly type the commands to enable the > backlight. Furthermore disabling backlight isn't always what you want to > do. For example if the bootloader already turned it on and you hand over > from bootloader to kernel in a seamless way, then you absolutely want to > keep backlight on all the time. > > See also[0] for a different proposal to solve the same problem. Back at > the time that received only a very few replies, but it would be nice if > Lee and Bryan could look at it again and see if we can come up with some > way to deal with this situation.
I don't have any experience with this stuff. Jingoo and Bryan are the _real_ reviewers for Backlight. I just maintain the patches. That and I'm already swamped with MFD. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
