Re: drivers/video/fbdev/au1100fb.c:448:46: error: implicit declaration of function 'KSEG1ADDR'; did you mean 'CKSEG1ADDR'?

[Helge Deller <deller@gmx.de>]

Hi Uwe,

On 3/5/26 09:07, Uwe Kleine-König wrote:
> On Wed, Mar 04, 2026 at 07:23:30PM +0100, Helge Deller wrote:
>> * kernel test robot <lkp@intel.com>:
>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>>> head:   0031c06807cfa8aa51a759ff8aa09e1aa48149af
>>> commit: 6f366e86481a7503a821de82930df517dddd4047 fbdev: au1100fb: Make driver compilable on non-mips platforms
>>> date:   13 days ago
>>> config: mips-randconfig-r052-20260304 (https://download.01.org/0day-ci/archive/20260304/202603042127.PT6LuKqi-lkp@intel.com/config)
>>> compiler: mips64-linux-gcc (GCC) 14.3.0
>>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260304/202603042127.PT6LuKqi-lkp@intel.com/reproduce)
>>>
>>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>>> the same patch/commit), kindly add following tags
>>> | Reported-by: kernel test robot <lkp@intel.com>
>>> | Closes: https://lore.kernel.org/oe-kbuild-all/202603042127.PT6LuKqi-lkp@intel.com/
>>>
>>> All error/warnings (new ones prefixed by >>):
>>>
>>>     drivers/video/fbdev/au1100fb.c: In function 'au1100fb_drv_probe':
>>>>> drivers/video/fbdev/au1100fb.c:448:46: error: implicit declaration of function 'KSEG1ADDR'; did you mean 'CKSEG1ADDR'? [-Wimplicit-function-declaration]
>>>       448 |         fbdev->regs = (struct au1100fb_regs*)KSEG1ADDR(fbdev->info.fix.mmio_start);
>>>           |                                              ^~~~~~~~~
>>>           |                                              CKSEG1ADDR
>>>>> drivers/video/fbdev/au1100fb.c:448:23: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>>>       448 |         fbdev->regs = (struct au1100fb_regs*)KSEG1ADDR(fbdev->info.fix.mmio_start);
>>>           |                       ^
>>
>> I've pushed the patch below into the fbdev git tree.
>> It should (hopefully) fix the issue.
>>
>> Helge
>>
>>
>> From: Helge Deller <deller@gmx.de>
>> Subject: [PATCH] fbdev: au1100fb: Fix build on MIPS64
>>
>> Fix an error reported by the kernel test robot:
>>   au1100fb.c: error: implicit declaration of function 'KSEG1ADDR'; did you mean 'CKSEG1ADDR'?
>>
>> The header asm/mach-au1x00/au1000.h is unused apart from pulling in
>> <linux/delay.h> (for mdelay()) and <linux/io.h> (for KSEG1ADDR()). Then
>> the only platform specific part in the driver is the usage of the KSEG1ADDR
>> macro, which for the non-mips case can be stubbed.
> 
> This paragraph is copied from 6f366e86481a and doesn't make sense here.

Yes, I noticed that later and removed it already.

> I'd write something like:
> 
> 	arch/mips/include/asm/addrspace.h defines KSEG1ADDR only for 32 bit
> 	configurations. So provide its compile-test stub also for 64bit
> 	mips builds.

Ok, added.

>> Fixes: 6f366e86481a ("fbdev: au1100fb: Make driver compilable on non-mips platforms")
>> Reported-by: kernel test robot <lkp@intel.com>
>> Closes: https://lore.kernel.org/oe-kbuild-all/202603042127.PT6LuKqi-lkp@intel.com/
>> Signed-off-by: Helge Deller <deller@gmx.de>
>> Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
>>
>> diff --git a/drivers/video/fbdev/au1100fb.c b/drivers/video/fbdev/au1100fb.c
>> index 1a04154bc535..3b104d377d28 100644
>> --- a/drivers/video/fbdev/au1100fb.c
>> +++ b/drivers/video/fbdev/au1100fb.c
>> @@ -380,7 +380,7 @@ static struct au1100fb_panel known_lcd_panels[] =
>>   #define panel_is_color(panel) (panel->control_base & LCD_CONTROL_PC)
>>   #define panel_swap_rgb(panel) (panel->control_base & LCD_CONTROL_CCO)
>>   
>> -#if defined(CONFIG_COMPILE_TEST) && !defined(CONFIG_MIPS)
>> +#if defined(CONFIG_COMPILE_TEST) && !(defined(CONFIG_MIPS) && !defined(CONFIG_64BIT))
> 
> The condition is equivalent to
> 
> 	defined(CONFIG_COMPILE_TEST) && (!defined(CONFIG_MIPS) || defined(CONFIG_64BIT))
> 
> which is logically a bit easier, but I'm unsure if it's easier to
> understand (IMHO both are bad).

Yes, both are bad. I changed it to your proposal.
  
>>   /* This is only defined to be able to compile this driver on non-mips platforms */
> 
> Maybe adapt the comment here, too? Something like:
> 
> 	/*
> 	 * KSEG1ADDR() is defined in arch/mips/include/asm/addrspace.h
> 	 * for 32 bit configurations. Provide a stub for compile testing
> 	 * on other platforms.
> 	 */

done.

I've updated the patch in the fbdev git tree, which you can find here:
https://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git/log/?h=for-next

I'll keep the patch a few days in there and will push next week.

Helge