Currently the CONFIG_FB option has to be enabled even if no legacy fbdev drivers are needed, in order to have support for a framebuffer console.

The DRM subsystem has a fbdev emulation layer, but depends on CONFIG_FB and so it can only be enabled if that dependency is enabled as well.

That means fbdev drivers have to be explicitly disabled if users want to enable CONFIG_FB, only to use fbcon with the DRM fbdev emulation layer.

This patch introduces a CONFIG_FB_CORE option that could be enabled just to have the core support needed for CONFIG_DRM_FBDEV_EMULATION, allowing CONFIG_FB to be disabled (and automatically disabling all fbdev drivers).

The fbsysfs.o object is left out of fb_core.o, because that's not needed for KMS drivers and the DRM fbdev emulation layer.

Signed-off-by: Javier Martinez Canillas javierm@redhat.com ---

arch/x86/Makefile | 2 +- arch/x86/video/Makefile | 2 +- drivers/video/console/Kconfig | 2 +- drivers/video/fbdev/Kconfig | 57 ++++++++++++++++++------------- drivers/video/fbdev/core/Makefile | 13 ++++--- include/linux/fb.h | 14 ++++++++ 6 files changed, 59 insertions(+), 31 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 44dd071d836..dc409539218 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -229,7 +229,7 @@ drivers-$(CONFIG_PCI) += arch/x86/pci/ # suspend and hibernation support drivers-$(CONFIG_PM) += arch/x86/power/

-drivers-$(CONFIG_FB) += arch/x86/video/ +drivers-$(CONFIG_FB_CORE) += arch/x86/video/

#### # boot loader support. Several targets are kept for legacy purposes diff --git a/arch/x86/video/Makefile b/arch/x86/video/Makefile index 11640c11611..cb0735bd662 100644 --- a/arch/x86/video/Makefile +++ b/arch/x86/video/Makefile @@ -1,2 +1,2 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-$(CONFIG_FB) += fbdev.o +obj-$(CONFIG_FB_CORE) += fbdev.o diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig index 840d9813b0b..0c562ed3495 100644 --- a/drivers/video/console/Kconfig +++ b/drivers/video/console/Kconfig @@ -71,7 +71,7 @@ config DUMMY_CONSOLE_ROWS

config FRAMEBUFFER_CONSOLE bool "Framebuffer Console support" - depends on FB && !UML + depends on FB_CORE && !UML select VT_HW_CONSOLE_BINDING select CRC32 select FONT_SUPPORT diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig index d33c5cd684c..cb9e8b503a5 100644 --- a/drivers/video/fbdev/Kconfig +++ b/drivers/video/fbdev/Kconfig @@ -9,10 +9,8 @@ config FB_CMDLINE config FB_NOTIFY bool

-menuconfig FB - tristate "Support for frame buffer devices" - select FB_CMDLINE - select FB_NOTIFY +menuconfig FB_CORE + tristate "Core support for frame buffer devices" help The frame buffer device provides an abstraction for the graphics hardware. It represents the frame buffer of some video hardware and @@ -36,6 +34,19 @@ menuconfig FB http://www.munted.org.uk/programming/Framebuffer-HOWTO-1.3.html for more information.

+ This options enables the core support for frame buffer devices. + +menuconfig FB + tristate "Support for frame buffer device drivers" + depends on FB_CORE + select FB_CMDLINE + select FB_NOTIFY + help + This enables support for frame buffer devices (fbdev) drivers. + + The DRM subsystem provides an option to emulate fbdev devices but + this option allows legacy fbdev drivers to be enabled as well. + Say Y here and to the driver for your graphics board below if you are compiling a kernel for a non-x86 architecture.

@@ -47,7 +58,7 @@ menuconfig FB

config FIRMWARE_EDID bool "Enable firmware EDID" - depends on FB + depends on FB_CORE help This enables access to the EDID transferred from the firmware. On the i386, this is from the Video BIOS. Enable this if DDC/I2C @@ -62,7 +73,7 @@ config FIRMWARE_EDID

config FB_DDC tristate - depends on FB + depends on FB_CORE select I2C_ALGOBIT select I2C

@@ -75,7 +86,7 @@ config FB_BOOT_VESA_SUPPORT

config FB_CFB_FILLRECT tristate - depends on FB + depends on FB_CORE help Include the cfb_fillrect function for generic software rectangle filling. This is used by drivers that don't provide their own @@ -83,7 +94,7 @@ config FB_CFB_FILLRECT

config FB_CFB_COPYAREA tristate - depends on FB + depends on FB_CORE help Include the cfb_copyarea function for generic software area copying. This is used by drivers that don't provide their own (accelerated) @@ -91,7 +102,7 @@ config FB_CFB_COPYAREA

config FB_CFB_IMAGEBLIT tristate - depends on FB + depends on FB_CORE help Include the cfb_imageblit function for generic software image blitting. This is used by drivers that don't provide their own @@ -99,7 +110,7 @@ config FB_CFB_IMAGEBLIT

config FB_CFB_REV_PIXELS_IN_BYTE bool - depends on FB + depends on FB_CORE help Allow generic frame-buffer functions to work on displays with 1, 2 and 4 bits per pixel depths which has opposite order of pixels in @@ -107,7 +118,7 @@ config FB_CFB_REV_PIXELS_IN_BYTE

config FB_SYS_FILLRECT tristate - depends on FB + depends on FB_CORE help Include the sys_fillrect function for generic software rectangle filling. This is used by drivers that don't provide their own @@ -115,7 +126,7 @@ config FB_SYS_FILLRECT

config FB_SYS_COPYAREA tristate - depends on FB + depends on FB_CORE help Include the sys_copyarea function for generic software area copying. This is used by drivers that don't provide their own (accelerated) @@ -123,7 +134,7 @@ config FB_SYS_COPYAREA

config FB_SYS_IMAGEBLIT tristate - depends on FB + depends on FB_CORE help Include the sys_imageblit function for generic software image blitting. This is used by drivers that don't provide their own @@ -131,14 +142,14 @@ config FB_SYS_IMAGEBLIT

config FB_PROVIDE_GET_FB_UNMAPPED_AREA bool - depends on FB + depends on FB_CORE help Allow generic frame-buffer to provide get_fb_unmapped_area function.

menuconfig FB_FOREIGN_ENDIAN bool "Framebuffer foreign endianness support" - depends on FB + depends on FB_CORE help This menu will let you enable support for the framebuffers with non-native endianness (e.g. Little-Endian framebuffer on a @@ -162,36 +173,36 @@ endchoice

config FB_SYS_FOPS tristate - depends on FB + depends on FB_CORE

config FB_DEFERRED_IO bool - depends on FB + depends on FB_CORE

config FB_HECUBA tristate - depends on FB + depends on FB_CORE depends on FB_DEFERRED_IO

config FB_SVGALIB tristate - depends on FB + depends on FB_CORE help Common utility functions useful to fbdev drivers of VGA-based cards.

config FB_MACMODES tristate - depends on FB + depends on FB_CORE

config FB_BACKLIGHT tristate - depends on FB + depends on FB_CORE select BACKLIGHT_CLASS_DEVICE

config FB_MODE_HELPERS bool "Enable Video Mode Handling Helpers" - depends on FB + depends on FB_CORE help This enables functions for handling video modes using the Generalized Timing Formula and the EDID parser. A few drivers rely @@ -201,7 +212,7 @@ config FB_MODE_HELPERS

config FB_TILEBLITTING bool "Enable Tile Blitting Support" - depends on FB + depends on FB_CORE help This enables tile blitting. Tile blitting is a drawing technique where the screen is divided into rectangular sections (tiles), whereas diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile index 26cbc965497..328a017c78b 100644 --- a/drivers/video/fbdev/core/Makefile +++ b/drivers/video/fbdev/core/Makefile @@ -1,22 +1,25 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_FB_CMDLINE) += fb_cmdline.o obj-$(CONFIG_FB_NOTIFY) += fb_notify.o +obj-$(CONFIG_FB_CORE) += fb_core.o obj-$(CONFIG_FB) += fb.o -fb-y := fbmem.o fbmon.o fbcmap.o fbsysfs.o \ +fb_core-y := fbmem.o fbmon.o fbcmap.o \ modedb.o fbcvt.o -fb-$(CONFIG_FB_DEFERRED_IO) += fb_defio.o +fb_core-$(CONFIG_FB_DEFERRED_IO) += fb_defio.o

ifeq ($(CONFIG_FRAMEBUFFER_CONSOLE),y) -fb-y += fbcon.o bitblit.o softcursor.o +fb_core-y += fbcon.o bitblit.o softcursor.o ifeq ($(CONFIG_FB_TILEBLITTING),y) -fb-y += tileblit.o +fb_core-y += tileblit.o endif ifeq ($(CONFIG_FRAMEBUFFER_CONSOLE_ROTATION),y) -fb-y += fbcon_rotate.o fbcon_cw.o fbcon_ud.o \ +fb_core-y += fbcon_rotate.o fbcon_cw.o fbcon_ud.o \ fbcon_ccw.o endif endif

+fb-y := fbsysfs.o + obj-$(CONFIG_FB_CFB_FILLRECT) += cfbfillrect.o obj-$(CONFIG_FB_CFB_COPYAREA) += cfbcopyarea.o obj-$(CONFIG_FB_CFB_IMAGEBLIT) += cfbimgblt.o diff --git a/include/linux/fb.h b/include/linux/fb.h index 96111248a25..f66eefbf1ee 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -689,9 +689,23 @@ static inline bool fb_be_math(struct fb_info *info) /* drivers/video/fbsysfs.c */ extern struct fb_info *framebuffer_alloc(size_t size, struct device *dev); extern void framebuffer_release(struct fb_info *info); +#if IS_ENABLED(CONFIG_FB) extern int fb_register_sysfs(struct fb_info *fb_info); extern void fb_unregister_sysfs(struct fb_info *head); extern void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max); +#else +static inline int fb_register_sysfs(struct fb_info *fb_info) +{ + return 0; +} +static inline void fb_unregister_sysfs(struct fb_info *head) +{ +} +static inline void fb_bl_default_curve(struct fb_info *fb_info, u8 off, + u8 min, u8 max) +{ +} +#endif

/* drivers/video/fbmon.c */ #define FB_MAXTIMINGS 0