Hi
Am 10.12.24 um 15:30 schrieb Arnd Bergmann:
On Tue, Dec 10, 2024, at 15:09, Thomas Zimmermann wrote:
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.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Thanks for revisiting this!
My patch that failed to work correctly happened to work on my
randconfig tree because I still have an old variant of this
change, see
https://lore.kernel.org/linux-fbdev/20200417155553.675905-8-arnd@xxxxxxxx/
This is almost the same as your version, except for the
optional fbdev Kconfig bits
PERS
@@ -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
+ select FB_BACKLIGHT
default y
help
Say Y here if you want to control the backlight of your display.
For instance here I used
@@ -702,6 +703,7 @@ 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
default y
help
Say Y here if you want to control the backlight of your display.
while your patch causes a link failure with
CONFIG_FB_NVIDIA=y
CONFIG_FB_NVIDIA_BACKLIGHT=y
CONFIG_BACKLIGHT_CLASS_DEVICE=m
Ah, right. I'll update the series to use your approach.
Best regards
Thomas
Arnd
--
--
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)
