On Tue, Sep 07, 2021 at 02:47:51PM +0200, Thomas Weißschuh wrote: > backlight.h documents "struct backlight_ops->get_brightness()" to return > a negative errno on failure. > So far these errors have not been handled in the backlight core. > This leads to negative values being exposed through sysfs although only > positive values are documented to be reported. > > Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx> Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> > --- > > v1: https://lore.kernel.org/dri-devel/20210906215525.15418-1-linux@xxxxxxxxxxxxxx/ > > v1 -> v2: > * use dev_err() instead of dev_warn() (Daniel Thompson) > * Finish logging format string with newline (Daniel Thompson) > * Log errno via dedicated error pointer format (Daniel Thompson) > > drivers/video/backlight/backlight.c | 22 +++++++++++++++++----- > 1 file changed, 17 insertions(+), 5 deletions(-) > > diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c > index 537fe1b376ad..4658cfb75aa2 100644 > --- a/drivers/video/backlight/backlight.c > +++ b/drivers/video/backlight/backlight.c > @@ -292,10 +292,13 @@ static ssize_t actual_brightness_show(struct device *dev, > struct backlight_device *bd = to_backlight_device(dev); > > mutex_lock(&bd->ops_lock); > - if (bd->ops && bd->ops->get_brightness) > - rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); > - else > + if (bd->ops && bd->ops->get_brightness) { > + rc = bd->ops->get_brightness(bd); > + if (rc >= 0) > + rc = sprintf(buf, "%d\n", rc); > + } else { > rc = sprintf(buf, "%d\n", bd->props.brightness); > + } > mutex_unlock(&bd->ops_lock); > > return rc; > @@ -381,9 +384,18 @@ ATTRIBUTE_GROUPS(bl_device); > void backlight_force_update(struct backlight_device *bd, > enum backlight_update_reason reason) > { > + int brightness; > + > mutex_lock(&bd->ops_lock); > - if (bd->ops && bd->ops->get_brightness) > - bd->props.brightness = bd->ops->get_brightness(bd); > + if (bd->ops && bd->ops->get_brightness) { > + brightness = bd->ops->get_brightness(bd); > + if (brightness >= 0) > + bd->props.brightness = brightness; > + else > + dev_err(&bd->dev, > + "Could not update brightness from device: %pe\n", > + ERR_PTR(brightness)); > + } > mutex_unlock(&bd->ops_lock); > backlight_generate_event(bd, reason); > } > > base-commit: 79fad92f2e596f5a8dd085788a24f540263ef887 > -- > 2.33.0 >
