vga16fb doesn't build on powerpc (vgacon_remap_base)

vga16fb doesn't build on powerpc (vgacon_remap_base)

[Joseph Fannin]

vga16fb is an available config option on powerpc, but it won't link
with my .config:

    ERROR: "vgacon_remap_base" [drivers/video/vga16fb.ko] undefined!


I'm guessing this is because include/asm-powerpc/vga.h declares
vgacon_remap_base: 

    extern unsigned long vgacon_remap_base;


...but arch/powerpc/kernel/setup_32.c wraps the definition in an #ifdef:

    #ifdef CONFIG_VGA_CONSOLE
    unsigned long vgacon_remap_base;
    EXPORT_SYMBOL(vgacon_remap_base);
    #endif


So CONFIG_VGA_CONSOLE=n and CONFIG_FB_VGA16=[y|m] won't work.

I've also noticed that the only places in the tree that ever assign
anything to config_remap_base are under arch/ppc.  And
include/asm-powerpc/vga.h also does this:

    #ifdef __powerpc64__
    #define VGA_MAP_MEM(x,s) ((unsigned long) ioremap((x), s))
    #else
    #define VGA_MAP_MEM(x,s) (x + vgacon_remap_base)
    #endif


So VGACON probably doesn't work either on 32bit.  I'm guessing arch/powerpc
doesn't support PREP.

How best could this be fixed up? Or should I just let the thing
be?  This is obviously not a new thing, and I don't have any hardware
that supports this stuff either.

--
Joseph Fannin
jfannin@gmail.com

Re: [Linux-fbdev-devel] vga16fb doesn't build on powerpc (vgacon_remap_base)

[Antonino A. Daplas]

On Tue, 2007-10-16 at 15:14 -0400, Joseph Fannin wrote:
> vga16fb is an available config option on powerpc, but it won't link
> with my .config:
> 
>     ERROR: "vgacon_remap_base" [drivers/video/vga16fb.ko] undefined!
> 
> 
> I'm guessing this is because include/asm-powerpc/vga.h declares
> vgacon_remap_base: 
> 
>     extern unsigned long vgacon_remap_base;
> 
> 
> ...but arch/powerpc/kernel/setup_32.c wraps the definition in an #ifdef:
> 
>     #ifdef CONFIG_VGA_CONSOLE

Perhaps #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_FB_VGA16) ?

or

bool VGA_HARDWARE

#if CONFIG_VGA_HARDWARE
    unsigned long vgacon_remap_base;
    EXPORT_SYMBOL(vgacon_remap_base);
#endif

and for the Kconfig entry of vgacon and vga16fb

select VGA_HARDWARE if PPC32
(or depends on (VGA_HARDWARE && PPC32))

Tony

Re: vga16fb doesn't build on powerpc (vgacon_remap_base)

[Geert Uytterhoeven]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 2040 bytes --]

On Tue, 16 Oct 2007, Joseph Fannin wrote:
> vga16fb is an available config option on powerpc, but it won't link
> with my .config:
> 
>     ERROR: "vgacon_remap_base" [drivers/video/vga16fb.ko] undefined!
> 
> 
> I'm guessing this is because include/asm-powerpc/vga.h declares
> vgacon_remap_base: 
> 
>     extern unsigned long vgacon_remap_base;
> 
> 
> ...but arch/powerpc/kernel/setup_32.c wraps the definition in an #ifdef:
> 
>     #ifdef CONFIG_VGA_CONSOLE
>     unsigned long vgacon_remap_base;
>     EXPORT_SYMBOL(vgacon_remap_base);
>     #endif
> 
> 
> So CONFIG_VGA_CONSOLE=n and CONFIG_FB_VGA16=[y|m] won't work.
> 
> I've also noticed that the only places in the tree that ever assign
> anything to config_remap_base are under arch/ppc.  And
> include/asm-powerpc/vga.h also does this:
> 
>     #ifdef __powerpc64__
>     #define VGA_MAP_MEM(x,s) ((unsigned long) ioremap((x), s))
>     #else
>     #define VGA_MAP_MEM(x,s) (x + vgacon_remap_base)
>     #endif
> 
> 
> So VGACON probably doesn't work either on 32bit.  I'm guessing arch/powerpc
> doesn't support PREP.

It's not only useful for PREP, but also for CHRP.

> How best could this be fixed up? Or should I just let the thing
> be?  This is obviously not a new thing, and I don't have any hardware
> that supports this stuff either.

I remember this problem was present when I still had a working LongTrail (which
is CHRP), long before arch/powerpc/ was created.

With kind regards,
 
Geert Uytterhoeven
Software Architect

Sony Network and Software Technology Center Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
 
Phone:    +32 (0)2 700 8453	
Fax:      +32 (0)2 700 8622	
E-mail:   Geert.Uytterhoeven@sonycom.com	
Internet: http://www.sony-europe.com/
 	
Sony Network and Software Technology Center Europe	
A division of Sony Service Centre (Europe) N.V.	
Registered office: Technologielaan 7 · B-1840 Londerzeel · Belgium	
VAT BE 0413.825.160 · RPR Brussels	
Fortis Bank Zaventem · Swift GEBABEBB08A · IBAN BE39001382358619

Re: vga16fb doesn't build on powerpc (vgacon_remap_base)

[Benjamin Herrenschmidt]

On Wed, 2007-10-17 at 10:49 +0200, Geert Uytterhoeven wrote:
> > 
> > So VGACON probably doesn't work either on 32bit.  I'm guessing
> arch/powerpc
> > doesn't support PREP.
> 
> It's not only useful for PREP, but also for CHRP.
> 
> > How best could this be fixed up? Or should I just let the thing
> > be?  This is obviously not a new thing, and I don't have any
> hardware
> > that supports this stuff either.
> 
> I remember this problem was present when I still had a working
> LongTrail (which
> is CHRP), long before arch/powerpc/ was created.

It's all very old stuff that needs to be dusted. If you have a setup
where legacy VGA is useable, feel free to do a bit of work on that :-)

Ben.