Re: [PATCH v2 1/3] fbdev: Fix recursive dependencies wrt BACKLIGHT_CLASS_DEVICE

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi


Am 13.12.24 um 08:44 schrieb Christophe Leroy:
> Le 12/12/2024 à 11:04, Thomas Zimmermann a écrit :
> > Do not select BACKLIGHT_CLASS_DEVICE from FB_BACKLIGHT. The latter
> > only controls backlight support within fbdev core code and data
> > structures.
> >
> > Make fbdev drivers depend on BACKLIGHT_CLASS_DEVICE and let users
> > select it explicitly. Fixes warnings about recursive dependencies,
> > such as
> >
> > error: recursive dependency detected!
> >     symbol BACKLIGHT_CLASS_DEVICE is selected by FB_BACKLIGHT
> >     symbol FB_BACKLIGHT is selected by FB_SH_MOBILE_LCDC
> >     symbol FB_SH_MOBILE_LCDC depends on FB_DEVICE
> >     symbol FB_DEVICE depends on FB_CORE
> >     symbol FB_CORE is selected by DRM_GEM_DMA_HELPER
> >     symbol DRM_GEM_DMA_HELPER is selected by DRM_PANEL_ILITEK_ILI9341
> >     symbol DRM_PANEL_ILITEK_ILI9341 depends on BACKLIGHT_CLASS_DEVICE
> >
> > BACKLIGHT_CLASS_DEVICE is user-selectable, so making drivers adapt to
> > it is the correct approach in any case. For most drivers, backlight
> > support is also configurable separately.
> >
> > v2:
> > - s/BACKLIGHT_DEVICE_CLASS/BACKLIGHT_CLASS_DEVICE (Helge)
> > - Fix fbdev driver-dependency corner case (Arnd)
> >
> > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> > ---
> >   drivers/auxdisplay/Kconfig       |  2 +-
> >   drivers/macintosh/Kconfig        |  1 +
> >   drivers/staging/fbtft/Kconfig    |  1 +
> >   drivers/video/fbdev/Kconfig      | 18 +++++++++++++-----
> >   drivers/video/fbdev/core/Kconfig |  3 +--
> >   5 files changed, 17 insertions(+), 8 deletions(-)
>
> Build fails which pmac32_defconfig :
>
>   LD      .tmp_vmlinux1
> powerpc64-linux-ld: drivers/macintosh/via-pmu-backlight.o: in function 
> `pmu_backlight_init':
> via-pmu-backlight.c:(.init.text+0xc0): undefined reference to 
> `backlight_device_register'
> make[2]: *** [scripts/Makefile.vmlinux:77: vmlinux] Error 1
> make[1]: *** [/home/chleroy/linux-powerpc/Makefile:1225: vmlinux] Error 2

The attached patch selects backlight support in the defconfigs that also 
have PMAC_BACKLIGHT=y. Can you please apply it on top of the patchset 
and report on the results?

Best regards
Thomas

> > diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
> > index 21545ffba065..8934e6ad5772 100644
> > --- a/drivers/auxdisplay/Kconfig
> > +++ b/drivers/auxdisplay/Kconfig
> > @@ -489,7 +489,7 @@ config IMG_ASCII_LCD
> >     config HT16K33
> >       tristate "Holtek Ht16K33 LED controller with keyscan"
> > -    depends on FB && I2C && INPUT
> > +    depends on FB && I2C && INPUT && BACKLIGHT_CLASS_DEVICE
> >       select FB_SYSMEM_HELPERS
> >       select INPUT_MATRIXKMAP
> >       select FB_BACKLIGHT
> > diff --git a/drivers/macintosh/Kconfig b/drivers/macintosh/Kconfig
> > index fb38f684444f..bf3824032d61 100644
> > --- a/drivers/macintosh/Kconfig
> > +++ b/drivers/macintosh/Kconfig
> > @@ -120,6 +120,7 @@ config PMAC_MEDIABAY
> >   config PMAC_BACKLIGHT
> >       bool "Backlight control for LCD screens"
> >       depends on PPC_PMAC && ADB_PMU && FB = y && (BROKEN || !PPC64)
> > +    depends on BACKLIGHT_CLASS_DEVICE
> >       select FB_BACKLIGHT
> >       help
> >         Say Y here to enable Macintosh specific extensions of the 
> > generic
> > diff --git a/drivers/staging/fbtft/Kconfig 
> > b/drivers/staging/fbtft/Kconfig
> > index 77ab44362f16..dcf6a70455cc 100644
> > --- a/drivers/staging/fbtft/Kconfig
> > +++ b/drivers/staging/fbtft/Kconfig
> > @@ -3,6 +3,7 @@ menuconfig FB_TFT
> >       tristate "Support for small TFT LCD display modules"
> >       depends on FB && SPI
> >       depends on FB_DEVICE
> > +    depends on BACKLIGHT_CLASS_DEVICE
> >       depends on GPIOLIB || COMPILE_TEST
> >       select FB_BACKLIGHT
> >       select FB_SYSMEM_HELPERS_DEFERRED
> > diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> > index de035071fedb..55c6686f091e 100644
> > --- a/drivers/video/fbdev/Kconfig
> > +++ b/drivers/video/fbdev/Kconfig
> > @@ -649,6 +649,7 @@ config FB_S1D13XXX
> >   config FB_ATMEL
> >       tristate "AT91 LCD Controller support"
> >       depends on FB && OF && HAVE_CLK && HAS_IOMEM
> > +    depends on BACKLIGHT_CLASS_DEVICE
> >       depends on HAVE_FB_ATMEL || COMPILE_TEST
> >       select FB_BACKLIGHT
> >       select FB_IOMEM_HELPERS
> > @@ -660,7 +661,6 @@ config FB_ATMEL
> >   config FB_NVIDIA
> >       tristate "nVidia Framebuffer Support"
> >       depends on FB && PCI
> > -    select FB_BACKLIGHT if FB_NVIDIA_BACKLIGHT
> >       select FB_CFB_FILLRECT
> >       select FB_CFB_COPYAREA
> >       select FB_CFB_IMAGEBLIT
> > @@ -700,6 +700,8 @@ config FB_NVIDIA_DEBUG
> >   config FB_NVIDIA_BACKLIGHT
> >       bool "Support for backlight control"
> >       depends on FB_NVIDIA
> > +    depends on BACKLIGHT_CLASS_DEVICE=y || 
> > BACKLIGHT_CLASS_DEVICE=FB_NVIDIA
> > +    select FB_BACKLIGHT
> >       default y
> >       help
> >         Say Y here if you want to control the backlight of your display.
> > @@ -707,7 +709,6 @@ config FB_NVIDIA_BACKLIGHT
> >   config FB_RIVA
> >       tristate "nVidia Riva support"
> >       depends on FB && PCI
> > -    select FB_BACKLIGHT if FB_RIVA_BACKLIGHT
> >       select FB_CFB_FILLRECT
> >       select FB_CFB_COPYAREA
> >       select FB_CFB_IMAGEBLIT
> > @@ -747,6 +748,8 @@ config FB_RIVA_DEBUG
> >   config FB_RIVA_BACKLIGHT
> >       bool "Support for backlight control"
> >       depends on FB_RIVA
> > +    depends on BACKLIGHT_CLASS_DEVICE=y || 
> > BACKLIGHT_CLASS_DEVICE=FB_RIVA
> > +    select FB_BACKLIGHT
> >       default y
> >       help
> >         Say Y here if you want to control the backlight of your display.
> > @@ -934,7 +937,6 @@ config FB_MATROX_MAVEN
> >   config FB_RADEON
> >       tristate "ATI Radeon display support"
> >       depends on FB && PCI
> > -    select FB_BACKLIGHT if FB_RADEON_BACKLIGHT
> >       select FB_CFB_FILLRECT
> >       select FB_CFB_COPYAREA
> >       select FB_CFB_IMAGEBLIT
> > @@ -960,6 +962,8 @@ config FB_RADEON_I2C
> >   config FB_RADEON_BACKLIGHT
> >       bool "Support for backlight control"
> >       depends on FB_RADEON
> > +    depends on BACKLIGHT_CLASS_DEVICE=y || 
> > BACKLIGHT_CLASS_DEVICE=FB_RADEON
> > +    select FB_BACKLIGHT
> >       default y
> >       help
> >         Say Y here if you want to control the backlight of your display.
> > @@ -975,7 +979,6 @@ config FB_RADEON_DEBUG
> >   config FB_ATY128
> >       tristate "ATI Rage128 display support"
> >       depends on FB && PCI
> > -    select FB_BACKLIGHT if FB_ATY128_BACKLIGHT
> >       select FB_IOMEM_HELPERS
> >       select FB_MACMODES if PPC_PMAC
> >       help
> > @@ -989,6 +992,8 @@ config FB_ATY128
> >   config FB_ATY128_BACKLIGHT
> >       bool "Support for backlight control"
> >       depends on FB_ATY128
> > +    depends on BACKLIGHT_CLASS_DEVICE=y || 
> > BACKLIGHT_CLASS_DEVICE=FB_ATY128
> > +    select FB_BACKLIGHT
> >       default y
> >       help
> >         Say Y here if you want to control the backlight of your display.
> > @@ -999,7 +1004,6 @@ config FB_ATY
> >       select FB_CFB_FILLRECT
> >       select FB_CFB_COPYAREA
> >       select FB_CFB_IMAGEBLIT
> > -    select FB_BACKLIGHT if FB_ATY_BACKLIGHT
> >       select FB_IOMEM_FOPS
> >       select FB_MACMODES if PPC
> >       select FB_ATY_CT if SPARC64 && PCI
> > @@ -1040,6 +1044,8 @@ config FB_ATY_GX
> >   config FB_ATY_BACKLIGHT
> >       bool "Support for backlight control"
> >       depends on FB_ATY
> > +    depends on BACKLIGHT_CLASS_DEVICE=y || 
> > BACKLIGHT_CLASS_DEVICE=FB_ATY
> > +    select FB_BACKLIGHT
> >       default y
> >       help
> >         Say Y here if you want to control the backlight of your display.
> > @@ -1528,6 +1534,7 @@ config FB_SH_MOBILE_LCDC
> >       depends on FB && HAVE_CLK && HAS_IOMEM
> >       depends on SUPERH || COMPILE_TEST
> >       depends on FB_DEVICE
> > +    depends on BACKLIGHT_CLASS_DEVICE
> >       select FB_BACKLIGHT
> >       select FB_DEFERRED_IO
> >       select FB_DMAMEM_HELPERS
> > @@ -1793,6 +1800,7 @@ config FB_SSD1307
> >       tristate "Solomon SSD1307 framebuffer support"
> >       depends on FB && I2C
> >       depends on GPIOLIB || COMPILE_TEST
> > +    depends on BACKLIGHT_CLASS_DEVICE
> >       select FB_BACKLIGHT
> >       select FB_SYSMEM_HELPERS_DEFERRED
> >       help
> > diff --git a/drivers/video/fbdev/core/Kconfig 
> > b/drivers/video/fbdev/core/Kconfig
> > index 0ab8848ba2f1..d554d8c543d4 100644
> > --- a/drivers/video/fbdev/core/Kconfig
> > +++ b/drivers/video/fbdev/core/Kconfig
> > @@ -183,9 +183,8 @@ config FB_SYSMEM_HELPERS_DEFERRED
> >       select FB_SYSMEM_HELPERS
> >     config FB_BACKLIGHT
> > -    tristate
> > +    bool
> >       depends on FB
> > -    select BACKLIGHT_CLASS_DEVICE
> >     config FB_MODE_HELPERS
> >       bool "Enable Video Mode Handling Helpers"

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

From b0283396aeed19cef8e1340c05103929cb41faf6 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@xxxxxxx>
Date: Fri, 13 Dec 2024 09:02:41 +0100
Subject: [PATCH] add BACKLIGHT_CLASS_DEVICE on PPC defconfigs

---
 arch/powerpc/configs/pmac32_defconfig | 1 +
 arch/powerpc/configs/ppc6xx_defconfig | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/powerpc/configs/pmac32_defconfig b/arch/powerpc/configs/pmac32_defconfig
index 57ded82c2840..e8b3f67bf3f5 100644
--- a/arch/powerpc/configs/pmac32_defconfig
+++ b/arch/powerpc/configs/pmac32_defconfig
@@ -208,6 +208,7 @@ CONFIG_FB_ATY=y
 CONFIG_FB_ATY_CT=y
 CONFIG_FB_ATY_GX=y
 CONFIG_FB_3DFX=y
+CONFIG_BACKLIGHT_CLASS_DEVICE=y
 # CONFIG_VGA_CONSOLE is not set
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_LOGO=y
diff --git a/arch/powerpc/configs/ppc6xx_defconfig b/arch/powerpc/configs/ppc6xx_defconfig
index 4d77e17541e9..ca0c90e95837 100644
--- a/arch/powerpc/configs/ppc6xx_defconfig
+++ b/arch/powerpc/configs/ppc6xx_defconfig
@@ -716,6 +716,7 @@ CONFIG_FB_TRIDENT=m
 CONFIG_FB_SM501=m
 CONFIG_FB_IBM_GXT4500=y
 CONFIG_LCD_PLATFORM=m
+CONFIG_BACKLIGHT_CLASS_DEVICE=y
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
 CONFIG_LOGO=y
-- 
2.47.1