linux-kernel - Re: [PATCH v2 3/3] arch/powerpc: Remove <linux/fb.h> from backlight code

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Message-ID: <f7503198-ab1b-463c-a8c8-9addbdcdab1b@suse.de>
Date: Tue, 5 Mar 2024 11:04:25 +0100
From: Thomas Zimmermann <tzimmermann@...e.de>
To: Christophe Leroy <christophe.leroy@...roup.eu>,
 "mpe@...erman.id.au" <mpe@...erman.id.au>,
 "jani.nikula@...el.com" <jani.nikula@...el.com>,
 "naresh.kamboju@...aro.org" <naresh.kamboju@...aro.org>,
 "deller@....de" <deller@....de>, "npiggin@...il.com" <npiggin@...il.com>,
 "aneesh.kumar@...nel.org" <aneesh.kumar@...nel.org>,
 "naveen.n.rao@...ux.ibm.com" <naveen.n.rao@...ux.ibm.com>
Cc: "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
 "linux-fbdev@...r.kernel.org" <linux-fbdev@...r.kernel.org>,
 "lkft-triage@...ts.linaro.org" <lkft-triage@...ts.linaro.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH v2 3/3] arch/powerpc: Remove <linux/fb.h> from backlight
 code

Hi

Am 05.03.24 um 10:25 schrieb Christophe Leroy:
>
> Le 05/03/2024 à 10:01, Thomas Zimmermann a écrit :
>> Replace <linux/fb.h> with a forward declaration in <asm/backlight.h> to
>> resolves an unnecessary dependency. Remove pmac_backlight_curve_lookup()
>> and struct fb_info from source and header files. The function and the
>> framebuffer struct is unused. No functional changes.
> When you remove pmac_backlight_curve_lookup() prototype you'll then get
> a warning/error about missing prototype when building
> arch/powerpc/platforms/powermac/backlight.c
>
> The fonction is not used outside of that file so it should be static.
> And then it is not used in that file either so it should be removed
> completely. Indeed last use of that function was removed by commit
> d565dd3b0824 ("[PATCH] powerpc: More via-pmu backlight fixes") so the
> function can safely be removed.

Isn't that what my patch is doing? I have no callers of the function in 
my tree (drm-tip), so I removed it entirely. Should I add a Fixes tag 
against commit d565dd3b0824? Best regards Thomas
>
> Christophe
>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
>> ---
>>    arch/powerpc/include/asm/backlight.h        |  5 ++--
>>    arch/powerpc/platforms/powermac/backlight.c | 26 ---------------------
>>    2 files changed, 2 insertions(+), 29 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/backlight.h b/arch/powerpc/include/asm/backlight.h
>> index 1b5eab62ed047..061a910d74929 100644
>> --- a/arch/powerpc/include/asm/backlight.h
>> +++ b/arch/powerpc/include/asm/backlight.h
>> @@ -10,15 +10,14 @@
>>    #define __ASM_POWERPC_BACKLIGHT_H
>>    #ifdef __KERNEL__
>>    
>> -#include <linux/fb.h>
>>    #include <linux/mutex.h>
>>    
>> +struct backlight_device;
>> +
>>    /* For locking instructions, see the implementation file */
>>    extern struct backlight_device *pmac_backlight;
>>    extern struct mutex pmac_backlight_mutex;
>>    
>> -extern int pmac_backlight_curve_lookup(struct fb_info *info, int value);
>> -
>>    extern int pmac_has_backlight_type(const char *type);
>>    
>>    extern void pmac_backlight_key(int direction);
>> diff --git a/arch/powerpc/platforms/powermac/backlight.c b/arch/powerpc/platforms/powermac/backlight.c
>> index aeb79a8b3e109..12bc01353bd3c 100644
>> --- a/arch/powerpc/platforms/powermac/backlight.c
>> +++ b/arch/powerpc/platforms/powermac/backlight.c
>> @@ -9,7 +9,6 @@
>>     */
>>    
>>    #include <linux/kernel.h>
>> -#include <linux/fb.h>
>>    #include <linux/backlight.h>
>>    #include <linux/adb.h>
>>    #include <linux/pmu.h>
>> @@ -72,31 +71,6 @@ int pmac_has_backlight_type(const char *type)
>>    	return 0;
>>    }
>>    
>> -int pmac_backlight_curve_lookup(struct fb_info *info, int value)
>> -{
>> -	int level = (FB_BACKLIGHT_LEVELS - 1);
>> -
>> -	if (info && info->bl_dev) {
>> -		int i, max = 0;
>> -
>> -		/* Look for biggest value */
>> -		for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
>> -			max = max((int)info->bl_curve[i], max);
>> -
>> -		/* Look for nearest value */
>> -		for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
>> -			int diff = abs(info->bl_curve[i] - value);
>> -			if (diff < max) {
>> -				max = diff;
>> -				level = i;
>> -			}
>> -		}
>> -
>> -	}
>> -
>> -	return level;
>> -}
>> -
>>    static void pmac_backlight_key_worker(struct work_struct *work)
>>    {
>>    	if (atomic_read(&kernel_backlight_disabled))

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)