Re: [PATCH 2/2] macintosh/via-pmu-backlight: Include linux/of.h and uapi/linux/fb.h

[Nathan Chancellor <nathan@kernel.org>]

On Tue, Nov 04, 2025 at 01:43:26PM +0100, Thomas Zimmermann wrote:
> Hi
> 
> Am 26.09.25 um 01:46 schrieb Nathan Chancellor:
> > After the recent removal of the fb.h include from backlight.h, which
> > transitively included of.h, there are several errors from
> > via-pmu-backlight.c (errors from bl_curve not being properly defined
> > omitted):
> > 
> >    drivers/macintosh/via-pmu-backlight.c:22:20: error: 'FB_BACKLIGHT_LEVELS' undeclared here (not in a function)
> >       22 | static u8 bl_curve[FB_BACKLIGHT_LEVELS];
> >          |                    ^~~~~~~~~~~~~~~~~~~
> >    drivers/macintosh/via-pmu-backlight.c: In function 'pmu_backlight_get_level_brightness':
> >    drivers/macintosh/via-pmu-backlight.c:63:38: error: 'FB_BACKLIGHT_MAX' undeclared (first use in this function); did you mean 'BACKLIGHT_RAW'?
> >       63 |         pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
> >          |                                      ^~~~~~~~~~~~~~~~
> >          |                                      BACKLIGHT_RAW
> >    drivers/macintosh/via-pmu-backlight.c: In function 'pmu_backlight_init':
> >    drivers/macintosh/via-pmu-backlight.c:144:17: error: implicit declaration of function 'of_machine_is_compatible' [-Wimplicit-function-declaration]
> >      144 |                 of_machine_is_compatible("AAPL,3400/2400") ||
> >          |                 ^~~~~~~~~~~~~~~~~~~~~~~~
> > 
> > FB_BACKLIGHT_{LEVELS,MAX} are available from the userspace API fb.h so
> > just include that avoid dragging in the full fb.h header unnecessarily.
> > Include linux/of.h for of_machine_is_compatible().
> > 
> > Fixes: 9f218f9bb9d2 ("backlight: Do not include <linux/fb.h> in header file")
> > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> > ---
> >   drivers/macintosh/via-pmu-backlight.c | 2 ++
> >   1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/macintosh/via-pmu-backlight.c b/drivers/macintosh/via-pmu-backlight.c
> > index 26bd9ed5e664..f7b7853b3802 100644
> > --- a/drivers/macintosh/via-pmu-backlight.c
> > +++ b/drivers/macintosh/via-pmu-backlight.c
> > @@ -11,7 +11,9 @@
> >   #include <asm/ptrace.h>
> >   #include <linux/adb.h>
> >   #include <linux/backlight.h>
> > +#include <linux/of.h>
> >   #include <linux/pmu.h>
> > +#include <uapi/linux/fb.h>
> 
> Should this not be <linux/fb.h> ?

It could be but as I mention above, this file only needs the UAPI
FB_BACKLIGHT_LEVELS and FB_BACKLIGHT_MAX constants so I did not really
feel like it was worth it to drag in the whole fb.h header.

> >   #include <asm/backlight.h>
> >   #define MAX_PMU_LEVEL 0xFF
> > 
> 
> -- 
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
> GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)
> 
>