While Documentation/kbuild/kconfig-language.rst provides a brief
explanation, there are recurring confusions regarding the usage of a
prompt followed by 'if <expr>'. This conditional controls _only_ the
prompt.
A typical usage is as follows:
menuconfig BLOCK
bool "Enable the block layer" if EXPERT
default y
When EXPERT=n, the prompt is hidden, but this config entry is still
active, and BLOCK is set to its default value 'y'. This is reasonable
because you are likely want to enable the block device support. When
EXPERT=y, the prompt is shown, allowing you to toggle BLOCK.
Please note that it is different from 'depends on EXPERT', which would
disable the entire config entry.
However, this conditional prompt has never worked for a choice.
The following two work in the same way: when EXPERT is disabled, the
choice block is entirely disabled.
[Test Code 1]
choice
prompt "choose" if EXPERT
config A
bool "A"
config B
bool "B"
endchoice
[Test Code 2]
choice
prompt "choose"
depends on EXPERT
config A
bool "A"
config B
bool "B"
endchoice
I believe the first case should hide only the prompt, but still produce
the default of the choice block:
CONFIG_A=y
# CONFIG_B is not set
The next commit will change (fix) the behavior of the conditional prompt
in choice blocks.
I see several choice blocks wrongly using a conditional prompt, where
'depends on' makes more sense.
To preserve the current behavior, this commit converts such misuses.
I did not touch the following hunk in arch/x86/Kconfig:
choice
prompt "Memory split" if EXPERT
default VMSPLIT_3G
This is truly the correct use of the conditional prompt; when EXPERT=n,
this choice block should silently select the reasonable VMSPLIT_3G,
although the resulting PAGE_OFFSET will not be affected anyway.
Presumably, the one in fs/jffs2/Kconfig is also correct, but I converted
it to 'depends on' to avoid any potential behavioral change.
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---
arch/arm/Kconfig | 6 ++++--
arch/arm64/Kconfig | 3 ++-
arch/mips/Kconfig | 6 ++++--
arch/powerpc/Kconfig | 3 ++-
arch/riscv/Kconfig | 3 ++-
fs/jffs2/Kconfig | 3 ++-
6 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ee5115252aac..a5bf65b06c53 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1482,7 +1482,8 @@ config ARM_ATAG_DTB_COMPAT
from the ATAG list and store it at run time into the appended DTB.
choice
- prompt "Kernel command line type" if ARM_ATAG_DTB_COMPAT
+ prompt "Kernel command line type"
+ depends on ARM_ATAG_DTB_COMPAT
default ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER
config ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER
@@ -1511,7 +1512,8 @@ config CMDLINE
memory size and the root device (e.g., mem=64M root=/dev/nfs).
choice
- prompt "Kernel command line type" if CMDLINE != ""
+ prompt "Kernel command line type"
+ depends on CMDLINE != ""
default CMDLINE_FROM_BOOTLOADER
config CMDLINE_FROM_BOOTLOADER
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5d91259ee7b5..c87d16b12e9b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2302,7 +2302,8 @@ config CMDLINE
root device (e.g. root=/dev/nfs).
choice
- prompt "Kernel command line type" if CMDLINE != ""
+ prompt "Kernel command line type"
+ depends on CMDLINE != ""
default CMDLINE_FROM_BOOTLOADER
help
Choose how the kernel will handle the provided default kernel
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index f1aa1bf11166..8cbc23f0c1a7 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2924,7 +2924,8 @@ config BUILTIN_DTB
bool
choice
- prompt "Kernel appended dtb support" if USE_OF
+ prompt "Kernel appended dtb support"
+ depends on USE_OF
default MIPS_NO_APPENDED_DTB
config MIPS_NO_APPENDED_DTB
@@ -2965,7 +2966,8 @@ choice
endchoice
choice
- prompt "Kernel command line type" if !CMDLINE_OVERRIDE
+ prompt "Kernel command line type"
+ depends on !CMDLINE_OVERRIDE
default MIPS_CMDLINE_FROM_DTB if USE_OF && !ATH79 && !MACH_INGENIC && \
!MACH_LOONGSON64 && !MIPS_MALTA && \
!CAVIUM_OCTEON_SOC
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c88c6d46a5bc..68e35b33e123 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -965,7 +965,8 @@ config CMDLINE
most cases you will need to specify the root device here.
choice
- prompt "Kernel command line type" if CMDLINE != ""
+ prompt "Kernel command line type"
+ depends on CMDLINE != ""
default CMDLINE_FROM_BOOTLOADER
config CMDLINE_FROM_BOOTLOADER
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 0525ee2d63c7..48b7faf62d0b 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -914,7 +914,8 @@ config CMDLINE
line here and choose how the kernel should use it later on.
choice
- prompt "Built-in command line usage" if CMDLINE != ""
+ prompt "Built-in command line usage"
+ depends on CMDLINE != ""
default CMDLINE_FALLBACK
help
Choose how the kernel will handle the provided built-in command
diff --git a/fs/jffs2/Kconfig b/fs/jffs2/Kconfig
index 7c96bc107218..560187d61562 100644
--- a/fs/jffs2/Kconfig
+++ b/fs/jffs2/Kconfig
@@ -151,8 +151,9 @@ config JFFS2_RUBIN
RUBINMIPS and DYNRUBIN compressors. Say 'N' if unsure.
choice
- prompt "JFFS2 default compression mode" if JFFS2_COMPRESSION_OPTIONS
+ prompt "JFFS2 default compression mode"
default JFFS2_CMODE_PRIORITY
+ depends on JFFS2_COMPRESSION_OPTIONS
depends on JFFS2_FS
help
You can set here the default compression mode of JFFS2 from
--
2.43.0
