[PATCH] fbdev: Clean up framebuffer initialization

This patch probably deserves discussion among developers.

Currently, the framebuffer system is initialized in a roundabout manner.
First, drivers/char/mem.c calls fbmem_init().  fbmem_init() will then
iterate over an array of individual drivers' xxxfb_init(), then each driver
registers its presence back to fbmem.  During console_init(),
drivers/char/vt.c will call fb_console_init().  fbcon will check for
registered drivers, and if any are present, will call take_over_console()
in drivers/char/vt.c.

This patch changes the initialization sequence so it proceeds in this
manner: Each driver has its own module_init().  Each driver calls
register_framebuffer() in fbmem.c.  fbmem.c will then notify fbcon of the
driver registration.  Upon notification, fbcon calls take_over_console() in
vt.c.

The following are the changes brought about by this patch:

- Each subsystem (fbcon, fbmem, xxxfb) will have their own module_init. 
  Thus, explicit calls to each subsystem's init functions are eliminated.

- The struct fb_drivers array in fbmem.c can be removed.  This slashes
  around 400 lines in fbmem.c

- Parsing of kernel boot options were done by fbmem.c calling each
  driver's xxxfb_setup() function.  Because this is not possible with this
  patch, drivers can choose to either:

  - have their own __setup() routine

  - call fb_get_options("xxxfb") and pass the return value to
    xxxfb_setup().  This is to maintain compatibility with the
    'video=xxxfb:<options>' semantics.

- Getting a framebuffer console will occur a bit late during the boot
  process since the initialization sequence will depend upon the link
  order.  So, 'video/' is moved up in drivers/Makefile, shortly after
  'pci/'

- Because driver initialization will be dependent on the link order,
  hardware that depends on other subsystems (agpgart, usb, serial, etc) may
  choose to initialize after the subsystems they depend on. 
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/Makefile

@@ -7,6 +7,7 @@
 
 obj-$(CONFIG_PCI)		+= pci/
 obj-$(CONFIG_PARISC)		+= parisc/
+obj-y				+= video/
 obj-$(CONFIG_ACPI_BOOT)		+= acpi/
 # PnP must come after ACPI since it will eventually need to check if acpi
 # was used and do nothing if so
@@ -26,7 +27,7 @@ obj-$(CONFIG_FC4)		+= fc4/
 obj-$(CONFIG_SCSI)		+= scsi/
 obj-$(CONFIG_FUSION)		+= message/
 obj-$(CONFIG_IEEE1394)		+= ieee1394/
-obj-y				+= cdrom/ video/
+obj-y				+= cdrom/
 obj-$(CONFIG_MTD)		+= mtd/
 obj-$(CONFIG_PCMCIA)		+= pcmcia/
 obj-$(CONFIG_DIO)		+= dio/

drivers/char/mem.c

@@ -31,9 +31,6 @@
 # include <linux/efi.h>
 #endif
 
-#ifdef CONFIG_FB
-extern void fbmem_init(void);
-#endif
 #if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR)
 extern void tapechar_init(void);
 #endif
@@ -730,9 +727,6 @@ static int __init chr_dev_init(void)
 				S_IFCHR | devlist[i].mode, devlist[i].name);
 	}
 	
-#if defined (CONFIG_FB)
-	fbmem_init();
-#endif
 	return 0;
 }
 

drivers/char/vt.c

@@ -136,9 +136,6 @@ extern void prom_con_init(void);
 #ifdef CONFIG_MDA_CONSOLE
 extern int mda_console_init(void);
 #endif
-#ifdef CONFIG_FRAMEBUFFER_CONSOLE
-extern int fb_console_init(void);
-#endif
 
 struct vc vc_cons [MAX_NR_CONSOLES];
 
@@ -2671,9 +2668,6 @@ int __init vty_init(void)
 #endif
 #ifdef CONFIG_MDA_CONSOLE
 	mda_console_init();
-#endif
-#ifdef CONFIG_FRAMEBUFFER_CONSOLE
-	fb_console_init();
 #endif
 	return 0;
 }

drivers/video/Makefile

@@ -13,6 +13,7 @@ ifeq ($(CONFIG_FB),y)
 obj-$(CONFIG_PPC)                 += macmodes.o
 endif
 
+obj-$(CONFIG_FB_OF)               += offb.o cfbfillrect.o cfbimgblt.o cfbcopyarea.o
 obj-$(CONFIG_FB_ARMCLCD)	  += amba-clcd.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
 obj-$(CONFIG_FB_ACORN)            += acornfb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
 obj-$(CONFIG_FB_AMIGA)            += amifb.o c2p.o
@@ -40,16 +41,12 @@ obj-$(CONFIG_FB_3DFX)             += cfbfillrect.o cfbcopyarea.o
 endif
 obj-$(CONFIG_FB_MAC)              += macfb.o macmodes.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o 
 obj-$(CONFIG_FB_HP300)            += hpfb.o cfbfillrect.o cfbimgblt.o
-obj-$(CONFIG_FB_OF)               += offb.o cfbfillrect.o cfbimgblt.o cfbcopyarea.o
 obj-$(CONFIG_FB_IMSTT)            += imsttfb.o cfbimgblt.o
 obj-$(CONFIG_FB_RETINAZ3)         += retz3fb.o
 obj-$(CONFIG_FB_CIRRUS)		  += cirrusfb.o cfbfillrect.o cfbimgblt.o cfbcopyarea.o
 obj-$(CONFIG_FB_TRIDENT)	  += tridentfb.o cfbfillrect.o cfbimgblt.o cfbcopyarea.o
 obj-$(CONFIG_FB_S3TRIO)           += S3triofb.o
 obj-$(CONFIG_FB_TGA)              += tgafb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o 
-obj-$(CONFIG_FB_VESA)             += vesafb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o 
-obj-$(CONFIG_FB_VGA16)            += vga16fb.o cfbfillrect.o cfbcopyarea.o \
-	                             cfbimgblt.o vgastate.o 
 obj-$(CONFIG_FB_VIRGE)            += virgefb.o
 obj-$(CONFIG_FB_G364)             += g364fb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
 obj-$(CONFIG_FB_FM2)              += fm2fb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
@@ -71,7 +68,6 @@ obj-$(CONFIG_FB_I810)             += i810/ cfbfillrect.o cfbcopyarea.o \
 obj-$(CONFIG_FB_SUN3)             += sun3fb.o
 obj-$(CONFIG_FB_HGA)              += hgafb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o 
 obj-$(CONFIG_FB_SA1100)           += sa1100fb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
-obj-$(CONFIG_FB_VIRTUAL)          += vfb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o 
 obj-$(CONFIG_FB_HIT)              += hitfb.o cfbfillrect.o cfbimgblt.o
 obj-$(CONFIG_FB_EPSON1355)	  += epson1355fb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
 obj-$(CONFIG_FB_PVR2)             += pvr2fb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
@@ -94,3 +90,7 @@ obj-$(CONFIG_FB_TCX)               += tcx.o sbuslib.o cfbimgblt.o cfbcopyarea.o
 obj-$(CONFIG_FB_LEO)               += leo.o sbuslib.o cfbimgblt.o cfbcopyarea.o \
 				      cfbfillrect.o
 obj-$(CONFIG_FB_PXA)		   += pxafb.o cfbimgblt.o cfbcopyarea.o cfbfillrect.o
+obj-$(CONFIG_FB_VGA16)            += vga16fb.o cfbfillrect.o cfbcopyarea.o \
+	                             cfbimgblt.o vgastate.o
+obj-$(CONFIG_FB_VESA)             += vesafb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o
+obj-$(CONFIG_FB_VIRTUAL)          += vfb.o cfbfillrect.o cfbcopyarea.o cfbimgblt.o

drivers/video/console/fbcon.c

@@ -2860,6 +2860,8 @@ int __init fb_console_init(void)
 	return 0;
 }
 
+module_init(fb_console_init);
+
 #ifdef MODULE
 
 void __exit fb_console_exit(void)
@@ -2870,7 +2872,6 @@ void __exit fb_console_exit(void)
 	give_up_console(&fb_con);
 }	
 
-module_init(fb_console_init);
 module_exit(fb_console_exit);
 
 #endif

include/linux/fb.h

@@ -708,6 +708,7 @@ extern void fb_sysmove_buf_aligned(struct fb_info *info, struct fb_pixmap *buf,
 extern void fb_load_cursor_image(struct fb_info *);
 extern void fb_set_suspend(struct fb_info *info, int state);
 extern int fb_get_color_depth(struct fb_info *info);
+extern char* fb_get_options(char *name);
 
 extern struct fb_info *registered_fb[FB_MAX];
 extern int num_registered_fb;