Re: [RFC PATCH] fbdev: maxinefb: fix build issues
From: Randy Dunlap
Date: Sun Aug 09 2026 - 23:29:46 EST
Hi,
On 8/9/26 8:24 PM, Philippe Mathieu-Daudé wrote:
> Hi Randy,
>
> On 10/8/26 01:48, Randy Dunlap wrote:
>> This is all ancient source code from the beginning of git time.
>> Now builds cleanly on 32-bit and 64-bit MACH_DECSTATION.
>>
>> Fixes these build errors/warnings:
>>
>> ../drivers/video/fbdev/maxinefb.c:64:6: warning: no previous prototype for 'maxinefb_ims332_write_register' [-Wmissing-prototypes]
>> 64 | void maxinefb_ims332_write_register(int regno, register unsigned int val)
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> In file included from ../drivers/video/fbdev/maxinefb.c:34:
>> ../drivers/video/fbdev/maxinefb.c: In function 'maxinefb_ims332_write_register':
>> ../include/video/maxinefb.h:16:41: error: implicit declaration of function 'KSEG1ADDR'; did you mean 'CKSEG1ADDR'? [-Wimplicit-function-declaration]
>> 16 | #define MAXINEFB_IMS332_ADDRESS KSEG1ADDR(0x1c140000)
>> | ^~~~~~~~~
>> ../drivers/video/fbdev/maxinefb.c:66:49: note: in expansion of macro 'MAXINEFB_IMS332_ADDRESS'
>> 66 | register unsigned char *regs = (char *) MAXINEFB_IMS332_ADDRESS;
>> | ^~~~~~~~~~~~~~~~~~~~~~~
>> ../drivers/video/fbdev/maxinefb.c:66:40: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>> 66 | register unsigned char *regs = (char *) MAXINEFB_IMS332_ADDRESS;
>> | ^
>> ../drivers/video/fbdev/maxinefb.c: At top level:
>> ../drivers/video/fbdev/maxinefb.c:74:14: warning: no previous prototype for 'maxinefb_ims332_read_register' [-Wmissing-prototypes]
>> 74 | unsigned int maxinefb_ims332_read_register(int regno)
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> ../drivers/video/fbdev/maxinefb.c: At top level:
>> ../drivers/video/fbdev/maxinefb.c:74:21: warning: 'maxinefb_ims332_read_register' defined but not used [-Wunused-function]
>> 74 | static unsigned int maxinefb_ims332_read_register(int regno)
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> ../drivers/video/fbdev/maxinefb.c: In function 'maxinefb_ims332_read_register':
>> ../drivers/video/fbdev/maxinefb.c:76:40: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>> 76 | register unsigned char *regs = (char *) MAXINEFB_IMS332_ADDRESS;
>> | ^
>> ../drivers/video/fbdev/maxinefb.c: At top level:
>> ../drivers/video/fbdev/maxinefb.c:114:12: warning: no previous prototype for 'maxinefb_init' [-Wmissing-prototypes]
>> 114 | int __init maxinefb_init(void)
>> | ^~~~~~~~~~~~~
>> In file included from ../drivers/video/fbdev/maxinefb.c:34:
>> ../drivers/video/fbdev/maxinefb.c: In function 'maxinefb_init':
>> ../include/video/maxinefb.h:22:41: error: implicit declaration of function 'KSEG1ADDR'; did you mean 'CKSEG1ADDR'? [-Wimplicit-function-declaration]
>> 22 | #define DS5000_xx_ONBOARD_FBMEM_START KSEG1ADDR(0x0a000000)
>> | ^~~~~~~~~
>> ../drivers/video/fbdev/maxinefb.c:119:20: note: in expansion of macro 'DS5000_xx_ONBOARD_FBMEM_START'
>> 119 | fb_start = DS5000_xx_ONBOARD_FBMEM_START;
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> Suggested-by: "Maciej W. Rozycki" <macro@xxxxxxxxxxx> # for s/KSEG1ADDR/CKSEG1ADDR/
>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>> ---
>> Cc: "Maciej W. Rozycki" <macro@xxxxxxxxxxx>
>> Cc: Helge Deller <deller@xxxxxx>
>> Cc: linux-fbdev@xxxxxxxxxxxxxxx
>> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
>> Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
>> Cc: linux-mips@xxxxxxxxxxxxxxx
>>
>> drivers/video/fbdev/maxinefb.c | 17 ++---------------
>> include/video/maxinefb.h | 4 ++--
>> 2 files changed, 4 insertions(+), 17 deletions(-)
>>
>> --- linux-next-20260807.orig/drivers/video/fbdev/maxinefb.c
>> +++ linux-next-20260807/drivers/video/fbdev/maxinefb.c
>> @@ -61,7 +61,7 @@ static struct fb_fix_screeninfo maxinefb
>> /* Handle the funny Inmos RamDAC/video controller ... */
>> -void maxinefb_ims332_write_register(int regno, register unsigned int val)
>> +static void maxinefb_ims332_write_register(int regno, register unsigned int val)
>> {
>> register unsigned char *regs = (char *) MAXINEFB_IMS332_ADDRESS;
>> unsigned char *wptr;
>> @@ -71,19 +71,6 @@ void maxinefb_ims332_write_register(int
>> *((volatile unsigned short *) (wptr)) = val;
>> }
>> -unsigned int maxinefb_ims332_read_register(int regno)
>> -{
>> - register unsigned char *regs = (char *) MAXINEFB_IMS332_ADDRESS;
>> - unsigned char *rptr;
>> - register unsigned int j, k;
>> -
>> - rptr = regs + 0x80000 + (regno << 4);
>> - j = *((volatile unsigned short *) rptr);
>> - k = *((volatile unsigned short *) regs);
>> -
>> - return (j & 0xffff) | ((k & 0xff00) << 8);
>> -}
>> -
>> /* Set the palette */
>> static int maxinefb_setcolreg(unsigned regno, unsigned red, unsigned green,
>> unsigned blue, unsigned transp, struct fb_info *info)
>> @@ -111,7 +98,7 @@ static const struct fb_ops maxinefb_ops
>> .fb_setcolreg = maxinefb_setcolreg,
>> };
>> -int __init maxinefb_init(void)
>> +static int __init maxinefb_init(void)
>> {
>> unsigned long fboff;
>> unsigned long fb_start;
>> --- linux-next-20260807.orig/include/video/maxinefb.h
>> +++ linux-next-20260807/include/video/maxinefb.h
>> @@ -13,13 +13,13 @@
>> /*
>> * IMS332 video controller register base address
>> */
>> -#define MAXINEFB_IMS332_ADDRESS KSEG1ADDR(0x1c140000)
>> +#define MAXINEFB_IMS332_ADDRESS CKSEG1ADDR(0x1c140000)
>> /*
>> * Begin of DECstation 5000/xx onboard framebuffer memory, default resolution
>> * is 1024x768x8
>> */
>> -#define DS5000_xx_ONBOARD_FBMEM_START KSEG1ADDR(0x0a000000)
>> +#define DS5000_xx_ONBOARD_FBMEM_START CKSEG1ADDR(0x0a000000)
>
> The change looks correct, but clearly this has never been tested
> on a 64-bit DECstation, so I'm not sure having this code being
> now built is an improvement.
>
> What about:
>
> -- >8 --
> diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> index ac9ac4287c6a..ff17afe6b8b3 100644
> --- a/drivers/video/fbdev/Kconfig
> +++ b/drivers/video/fbdev/Kconfig
> @@ -1436,7 +1436,7 @@ config FB_PMAGB_B
>
> config FB_MAXINE
> bool "Maxine (Personal DECstation) onboard framebuffer support"
> - depends on (FB = y) && MACH_DECSTATION
> + depends on (FB = y) && MACH_DECSTATION && 32BIT
> select FB_IOMEM_HELPERS
> help
> Support for the onboard framebuffer (1024x768x8) in the Personal
> ---
>
> ?
I guess I'm OK with that. I'm even OK with removing the driver completely.
Maciej did say in https://lore.kernel.org/all/alpine.DEB.2.21.2308152255080.8596@xxxxxxxxxxxxxxxxx/
that: "the proper way would be by using `ioremap' really. I'll make a patch."
[That was 15.Aug.2023.]
--
~Randy