| Message ID | 20230714171642.91185-4-javierm@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Allow disabling all native fbdev drivers and only keeping DRM emulation | expand |
On Fri, Jul 14, 2023, at 19:16, Javier Martinez Canillas wrote: > Currently the CONFIG_FB option has to be enabled even if no legacy fbdev > drivers are needed (e.g: only to have support for framebuffer consoles). > > 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 and/or the DRM fbdev emulation layer. > > This patch introduces a non-visible CONFIG_FB_CORE symbol that could be > enabled just to have core support needed for CONFIG_DRM_FBDEV_EMULATION, > allowing CONFIG_FB to be disabled (and automatically disabling all the > fbdev drivers). > > Nothing from fb_backlight.o and fbmon.o is used by the DRM fbdev emulation > layer so these two objects can be compiled out when CONFIG_FB is disabled. I gave this a spin in my randconfig build setup and found one small mistake: > diff --git a/drivers/video/fbdev/core/Makefile > b/drivers/video/fbdev/core/Makefile > index 9150bafd9e89..2cd213716c12 100644 > --- a/drivers/video/fbdev/core/Makefile > +++ b/drivers/video/fbdev/core/Makefile > @@ -1,10 +1,10 @@ > # SPDX-License-Identifier: GPL-2.0 > obj-$(CONFIG_FB_NOTIFY) += fb_notify.o > -obj-$(CONFIG_FB) += fb.o > -fb-y := fb_backlight.o \ > - fb_info.o \ > - fbmem.o fbmon.o fbcmap.o \ > +obj-$(CONFIG_FB_CORE) += fb.o > +fb-y := fb_info.o \ > + fbmem.o fbcmap.o \ > modedb.o fbcvt.o fb_cmdline.o > fb_io_fops.o > +fb-$(CONFIG_FB) += fb_backlight.o fbmon.o With CONFIG_FB_CORE=y and CONFIG_FB=m, Kbuild does not include the fb_backlight.o and fbmon.o files in fb.ko because they are not set to =y, causing link failures for fbdev drivers later: ERROR: modpost: "of_get_fb_videomode" [drivers/video/fbdev/clps711x-fb.ko] undefined! ERROR: modpost: "fb_videomode_from_videomode" [drivers/video/fbdev/atmel_lcdfb.ko] undefined! ERROR: modpost: "of_get_fb_videomode" [drivers/video/fbdev/imxfb.ko] undefined! ERROR: modpost: "fb_destroy_modedb" [drivers/video/fbdev/udlfb.ko] undefined! ERROR: modpost: "fb_edid_to_monspecs" [drivers/video/fbdev/udlfb.ko] undefined! ERROR: modpost: "fb_destroy_modedb" [drivers/video/fbdev/smscufx.ko] undefined! ERROR: modpost: "fb_edid_to_monspecs" [drivers/video/fbdev/smscufx.ko] undefined! ERROR: modpost: "fb_destroy_modedb" [drivers/video/fbdev/uvesafb.ko] undefined! ERROR: modpost: "fb_validate_mode" [drivers/video/fbdev/uvesafb.ko] undefined! ERROR: modpost: "fb_get_mode" [drivers/video/fbdev/uvesafb.ko] undefined! Folding this fixup into the patch makes it work: diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile index 2cd213716c12f..84ddc5d308b58 100644 --- a/drivers/video/fbdev/core/Makefile +++ b/drivers/video/fbdev/core/Makefile @@ -4,7 +4,9 @@ obj-$(CONFIG_FB_CORE) += fb.o fb-y := fb_info.o \ fbmem.o fbcmap.o \ modedb.o fbcvt.o fb_cmdline.o fb_io_fops.o -fb-$(CONFIG_FB) += fb_backlight.o fbmon.o +ifdef CONFIG_FB +fb-y += fb_backlight.o fbmon.o +endif fb-$(CONFIG_FB_DEFERRED_IO) += fb_defio.o fb-$(CONFIG_FB_DEVICE) += fb_chrdev.o \ fb_procfs.o \ Arnd
"Arnd Bergmann" <arnd@arndb.de> writes: > On Fri, Jul 14, 2023, at 19:16, Javier Martinez Canillas wrote: >> Currently the CONFIG_FB option has to be enabled even if no legacy fbdev >> drivers are needed (e.g: only to have support for framebuffer consoles). >> >> 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 and/or the DRM fbdev emulation layer. >> >> This patch introduces a non-visible CONFIG_FB_CORE symbol that could be >> enabled just to have core support needed for CONFIG_DRM_FBDEV_EMULATION, >> allowing CONFIG_FB to be disabled (and automatically disabling all the >> fbdev drivers). >> >> Nothing from fb_backlight.o and fbmon.o is used by the DRM fbdev emulation >> layer so these two objects can be compiled out when CONFIG_FB is disabled. > > I gave this a spin in my randconfig build setup and found one small > mistake: > Thanks for testing! >> diff --git a/drivers/video/fbdev/core/Makefile >> b/drivers/video/fbdev/core/Makefile >> index 9150bafd9e89..2cd213716c12 100644 >> --- a/drivers/video/fbdev/core/Makefile >> +++ b/drivers/video/fbdev/core/Makefile >> @@ -1,10 +1,10 @@ >> # SPDX-License-Identifier: GPL-2.0 >> obj-$(CONFIG_FB_NOTIFY) += fb_notify.o >> -obj-$(CONFIG_FB) += fb.o >> -fb-y := fb_backlight.o \ >> - fb_info.o \ >> - fbmem.o fbmon.o fbcmap.o \ >> +obj-$(CONFIG_FB_CORE) += fb.o >> +fb-y := fb_info.o \ >> + fbmem.o fbcmap.o \ >> modedb.o fbcvt.o fb_cmdline.o >> fb_io_fops.o >> +fb-$(CONFIG_FB) += fb_backlight.o fbmon.o > > With CONFIG_FB_CORE=y and CONFIG_FB=m, Kbuild does not include > the fb_backlight.o and fbmon.o files in fb.ko because they are not > set to =y, causing link failures for fbdev drivers later: > > ERROR: modpost: "of_get_fb_videomode" [drivers/video/fbdev/clps711x-fb.ko] undefined! > ERROR: modpost: "fb_videomode_from_videomode" [drivers/video/fbdev/atmel_lcdfb.ko] undefined! > ERROR: modpost: "of_get_fb_videomode" [drivers/video/fbdev/imxfb.ko] undefined! > ERROR: modpost: "fb_destroy_modedb" [drivers/video/fbdev/udlfb.ko] undefined! > ERROR: modpost: "fb_edid_to_monspecs" [drivers/video/fbdev/udlfb.ko] undefined! > ERROR: modpost: "fb_destroy_modedb" [drivers/video/fbdev/smscufx.ko] undefined! > ERROR: modpost: "fb_edid_to_monspecs" [drivers/video/fbdev/smscufx.ko] undefined! > ERROR: modpost: "fb_destroy_modedb" [drivers/video/fbdev/uvesafb.ko] undefined! > ERROR: modpost: "fb_validate_mode" [drivers/video/fbdev/uvesafb.ko] undefined! > ERROR: modpost: "fb_get_mode" [drivers/video/fbdev/uvesafb.ko] undefined! > Right, sorry for missing that combination. > > Folding this fixup into the patch makes it work: > > diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile > index 2cd213716c12f..84ddc5d308b58 100644 > --- a/drivers/video/fbdev/core/Makefile > +++ b/drivers/video/fbdev/core/Makefile > @@ -4,7 +4,9 @@ obj-$(CONFIG_FB_CORE) += fb.o > fb-y := fb_info.o \ > fbmem.o fbcmap.o \ > modedb.o fbcvt.o fb_cmdline.o fb_io_fops.o > -fb-$(CONFIG_FB) += fb_backlight.o fbmon.o > +ifdef CONFIG_FB > +fb-y += fb_backlight.o fbmon.o > +endif > fb-$(CONFIG_FB_DEFERRED_IO) += fb_defio.o > fb-$(CONFIG_FB_DEVICE) += fb_chrdev.o \ > fb_procfs.o \ > Perfect, I'll squash your fix in v6. Thanks!
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index b39975977c03..89a02e69be5f 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -259,7 +259,7 @@ 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 11640c116115..5ebe48752ffc 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/backlight/backlight.c b/drivers/video/backlight/backlight.c index 9a885d398c22..86e1cdc8e369 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -79,8 +79,8 @@ static const char *const backlight_scale_types[] = { [BACKLIGHT_SCALE_NON_LINEAR] = "non-linear", }; -#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ - defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) +#if defined(CONFIG_FB_CORE) || (defined(CONFIG_FB_CORE_MODULE) && \ + defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) /* * fb_notifier_callback * @@ -155,7 +155,7 @@ static inline int backlight_register_fb(struct backlight_device *bd) static inline void backlight_unregister_fb(struct backlight_device *bd) { } -#endif /* CONFIG_FB */ +#endif /* CONFIG_FB_CORE */ static void backlight_generate_event(struct backlight_device *bd, enum backlight_update_reason reason) diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig index a2a88d42edf0..1b5a319971ed 100644 --- a/drivers/video/console/Kconfig +++ b/drivers/video/console/Kconfig @@ -72,7 +72,7 @@ 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 ec4068abeb8e..7e65a648f71a 100644 --- a/drivers/video/fbdev/Kconfig +++ b/drivers/video/fbdev/Kconfig @@ -4,9 +4,9 @@ # menuconfig FB - tristate "Support for frame buffer devices" + tristate "Support for frame buffer device drivers" + select FB_CORE select FB_NOTIFY - select VIDEO_CMDLINE help The frame buffer device provides an abstraction for the graphics hardware. It represents the frame buffer of some video hardware and @@ -30,6 +30,12 @@ menuconfig FB <http://www.munted.org.uk/programming/Framebuffer-HOWTO-1.3.html> for more information. + This enables support for native frame buffer device (fbdev) drivers. + + The DRM subsystem provides support for emulated frame buffer devices + on top of KMS drivers, 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. diff --git a/drivers/video/fbdev/core/Kconfig b/drivers/video/fbdev/core/Kconfig index 8e308d12c57b..15ce529d579a 100644 --- a/drivers/video/fbdev/core/Kconfig +++ b/drivers/video/fbdev/core/Kconfig @@ -3,6 +3,10 @@ # fbdev core configuration # +config FB_CORE + select VIDEO_CMDLINE + tristate + config FB_NOTIFY bool @@ -23,7 +27,7 @@ config FIRMWARE_EDID config FB_DEVICE bool "Provide legacy /dev/fb* device" - depends on FB + depends on FB_CORE default y help Say Y here if you want the legacy /dev/fb* device file and @@ -39,7 +43,7 @@ config FB_DDC 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 @@ -47,7 +51,7 @@ 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) @@ -55,7 +59,7 @@ 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 @@ -63,7 +67,7 @@ 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 @@ -71,7 +75,7 @@ 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 @@ -79,7 +83,7 @@ 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) @@ -87,7 +91,7 @@ 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 @@ -126,22 +130,22 @@ 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_IO_HELPERS bool - depends on FB + depends on FB_CORE select FB_CFB_COPYAREA select FB_CFB_FILLRECT select FB_CFB_IMAGEBLIT config FB_SYS_HELPERS bool - depends on FB + depends on FB_CORE select FB_SYS_COPYAREA select FB_SYS_FILLRECT select FB_SYS_FOPS @@ -149,7 +153,7 @@ config FB_SYS_HELPERS config FB_SYS_HELPERS_DEFERRED bool - depends on FB + depends on FB_CORE select FB_DEFERRED_IO select FB_SYS_HELPERS diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile index 9150bafd9e89..2cd213716c12 100644 --- a/drivers/video/fbdev/core/Makefile +++ b/drivers/video/fbdev/core/Makefile @@ -1,10 +1,10 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_FB_NOTIFY) += fb_notify.o -obj-$(CONFIG_FB) += fb.o -fb-y := fb_backlight.o \ - fb_info.o \ - fbmem.o fbmon.o fbcmap.o \ +obj-$(CONFIG_FB_CORE) += fb.o +fb-y := fb_info.o \ + fbmem.o fbcmap.o \ modedb.o fbcvt.o fb_cmdline.o fb_io_fops.o +fb-$(CONFIG_FB) += fb_backlight.o fbmon.o fb-$(CONFIG_FB_DEFERRED_IO) += fb_defio.o fb-$(CONFIG_FB_DEVICE) += fb_chrdev.o \ fb_procfs.o \
Currently the CONFIG_FB option has to be enabled even if no legacy fbdev drivers are needed (e.g: only to have support for framebuffer consoles). 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 and/or the DRM fbdev emulation layer. This patch introduces a non-visible CONFIG_FB_CORE symbol that could be enabled just to have core support needed for CONFIG_DRM_FBDEV_EMULATION, allowing CONFIG_FB to be disabled (and automatically disabling all the fbdev drivers). Nothing from fb_backlight.o and fbmon.o is used by the DRM fbdev emulation layer so these two objects can be compiled out when CONFIG_FB is disabled. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> --- Changes in v5: - Fix ifdef guard check in drivers/video/backlight/backlight.c (Arnd Bergmann). Changes in v4: - Fix menuconfig hierarchy that was broken in v3 (Arnd Bergmann). Changes in v3: - Really make a hidden symbol by removing the prompt (Arnd Bergmann). - Change FB_CORE to config instead of menuconfig (Arnd Bergmann). - Keep "depends on FB" for FIRMWARE_EDID (Arnd Bergmann). - Compile out fb_backlight.o and fbmon.o that are only needed for FB (Arnd Bergmann). - Make FB_DEVICE to depend on FB_CORE instead of selecting it. Changes in v2: - Keep "depends on FB" for FB_DDC, FB_HECUBA, FB_SVGALIB, FB_MACMODES, FB_BACKLIGHT, FB_MODE_HELPERS and FB_TILEBLITTING (Arnd Bergmann). - Don't change the fb.o object name (Arnd Bergmann). - Make FB_CORE a non-visible Kconfig symbol instead (Thomas Zimmermann). arch/x86/Makefile | 2 +- arch/x86/video/Makefile | 2 +- drivers/video/backlight/backlight.c | 6 +++--- drivers/video/console/Kconfig | 2 +- drivers/video/fbdev/Kconfig | 10 ++++++++-- drivers/video/fbdev/core/Kconfig | 30 ++++++++++++++++------------- drivers/video/fbdev/core/Makefile | 8 ++++---- 7 files changed, 35 insertions(+), 25 deletions(-)