linux-kernel - Re: [PATCH] fbdev: atyfb: add stubs for aty_{ld,st}

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Date:   Wed, 24 Feb 2021 23:07:10 +0200
From:   Ville Syrjälä <ville.syrjala@...ux.intel.com>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     linux-kernel@...r.kernel.org, linux-fbdev@...r.kernel.org,
        kernel test robot <lkp@...el.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel@...ts.freedesktop.org, Sam Ravnborg <sam@...nborg.org>
Subject: Re: [PATCH] fbdev: atyfb: add stubs for aty_{ld,st}_lcd()

On Wed, Feb 24, 2021 at 11:59:45AM -0800, Randy Dunlap wrote:
> On 2/22/21 9:44 AM, Ville Syrjälä wrote:
> > On Sun, Feb 21, 2021 at 07:28:53PM -0800, Randy Dunlap wrote:
> >> Fix build errors when these functions are not defined.
> >>
> >> ../drivers/video/fbdev/aty/atyfb_base.c: In function 'aty_power_mgmt':
> >> ../drivers/video/fbdev/aty/atyfb_base.c:2002:7: error: implicit declaration of function 'aty_ld_lcd'; did you mean 'aty_ld_8'? [-Werror=implicit-function-declaration]
> >>  2002 |  pm = aty_ld_lcd(POWER_MANAGEMENT, par);
> >> ../drivers/video/fbdev/aty/atyfb_base.c:2004:2: error: implicit declaration of function 'aty_st_lcd'; did you mean 'aty_st_8'? [-Werror=implicit-function-declaration]
> >>  2004 |  aty_st_lcd(POWER_MANAGEMENT, pm, par);
> >> Signed-off-by: Randy Dunlap <rdunlap@...radead.org>
> >> Reported-by: kernel test robot <lkp@...el.com>
> >> Cc: linux-fbdev@...r.kernel.org
> >> Cc: dri-devel@...ts.freedesktop.org
> >> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> >> Cc: Sam Ravnborg <sam@...nborg.org>
> >> Cc: Daniel Vetter <daniel@...ll.ch>
> >> Cc: David Airlie <airlied@...ux.ie>
> >> Cc: Jani Nikula <jani.nikula@...ux.intel.com>
> >> ---
> >>  drivers/video/fbdev/aty/atyfb_base.c |    9 +++++++++
> >>  1 file changed, 9 insertions(+)
> >>
> >> --- linux-next-20210219.orig/drivers/video/fbdev/aty/atyfb_base.c
> >> +++ linux-next-20210219/drivers/video/fbdev/aty/atyfb_base.c
> >> @@ -175,6 +175,15 @@ u32 aty_ld_lcd(int index, const struct a
> >>  		return aty_ld_le32(LCD_DATA, par);
> >>  	}
> >>  }
> >> +#else /* defined(CONFIG_PMAC_BACKLIGHT) || defined(CONFIG_FB_ATY_BACKLIGHT) \
> >> +	 defined(CONFIG_FB_ATY_GENERIC_LCD) */
> > 
> > A better fix would seem to be to include these functions if
> > CONFIG_PPC_PMAC is enabled. Otherwise the PM code will surely
> > not work correctly. Though I'm not sure if that PPC PM
> > code makes any sense w/o LCD/backlight support anyway.
> 
> Hi Ville,
> 
> I tried this:
> 
> -#if defined(CONFIG_PMAC_BACKLIGHT) || defined(CONFIG_FB_ATY_GENERIC_LCD) || \
> -defined(CONFIG_FB_ATY_BACKLIGHT)
> +#if defined(CONFIG_PPC_PMAC)
> 
> in both atyfb_base.c and atyfb.h, but then there is a build error in
> mach64_ct.c when PPC_PMAC is not enabled but FB_ATY_GENERIC_LCD is enabled.
> [mach64_ct.c is the only other user of aty_{ld,st}_lcd()]
> 
> or did you mean adding CONFIG_PPC_PMAC to that longish #if list?
> (that's not how I understood your comment.)

Yeah, I meant adding ||PPC_PMAC to the existing set of conditions.
You definitely need to have this stuff for the LCD/backlight
support on !PPC_PMAC as well.

> 
> 
> I'll gladly step away and let you submit patches for this. :)

I don't have any powerbook/etc. hw to test this so couldn't
really add any extra value. Just have vague memories of touching
this stuff long ago so figured I'd provide my "expertise" :)

> 
> >> +void aty_st_lcd(int index, u32 val, const struct atyfb_par *par)
> >> +{ }
> >> +
> >> +u32 aty_ld_lcd(int index, const struct atyfb_par *par)
> >> +{
> >> +	return 0;
> >> +}
> >>  #endif /* defined(CONFIG_PMAC_BACKLIGHT) || defined (CONFIG_FB_ATY_GENERIC_LCD) */
> >>  
> >>  #ifdef CONFIG_FB_ATY_GENERIC_LCD
> >> _______________________________________________
> 
> 
> thanks.
> -- 
> ~Randy

-- 
Ville Syrjälä
Intel