<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/scripts/kconfig/expr.h, branch v4.19.269</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.19.269</id>
<link rel='self' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.19.269'/>
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<updated>2019-07-26T07:14:24Z</updated>
<entry>
<title>kconfig: fix missing choice values in auto.conf</title>
<updated>2019-07-26T07:14:24Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-07-12T06:07:09Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=c77cbc873586322b40401bc35262cddcf8cfefca'/>
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<content type='text'>
commit 8e2442a5f86e1f77b86401fce274a7f622740bc4 upstream.

Since commit 00c864f8903d ("kconfig: allow all config targets to write
auto.conf if missing"), Kconfig creates include/config/auto.conf in the
defconfig stage when it is missing.

Joonas Kylmälä reported incorrect auto.conf generation under some
circumstances.

To reproduce it, apply the following diff:

|  --- a/arch/arm/configs/imx_v6_v7_defconfig
|  +++ b/arch/arm/configs/imx_v6_v7_defconfig
|  @@ -345,14 +345,7 @@ CONFIG_USB_CONFIGFS_F_MIDI=y
|   CONFIG_USB_CONFIGFS_F_HID=y
|   CONFIG_USB_CONFIGFS_F_UVC=y
|   CONFIG_USB_CONFIGFS_F_PRINTER=y
|  -CONFIG_USB_ZERO=m
|  -CONFIG_USB_AUDIO=m
|  -CONFIG_USB_ETH=m
|  -CONFIG_USB_G_NCM=m
|  -CONFIG_USB_GADGETFS=m
|  -CONFIG_USB_FUNCTIONFS=m
|  -CONFIG_USB_MASS_STORAGE=m
|  -CONFIG_USB_G_SERIAL=m
|  +CONFIG_USB_FUNCTIONFS=y
|   CONFIG_MMC=y
|   CONFIG_MMC_SDHCI=y
|   CONFIG_MMC_SDHCI_PLTFM=y

And then, run:

$ make ARCH=arm mrproper imx_v6_v7_defconfig

You will see CONFIG_USB_FUNCTIONFS=y is correctly contained in the
.config, but not in the auto.conf.

Please note drivers/usb/gadget/legacy/Kconfig is included from a choice
block in drivers/usb/gadget/Kconfig. So USB_FUNCTIONFS is a choice value.

This is probably a similar situation described in commit beaaddb62540
("kconfig: tests: test defconfig when two choices interact").

When sym_calc_choice() is called, the choice symbol forgets the
SYMBOL_DEF_USER unless all of its choice values are explicitly set by
the user.

The choice symbol is given just one chance to recall it because
set_all_choice_values() is called if SYMBOL_NEED_SET_CHOICE_VALUES
is set.

When sym_calc_choice() is called again, the choice symbol forgets it
forever, since SYMBOL_NEED_SET_CHOICE_VALUES is a one-time aid.
Hence, we cannot call sym_clear_all_valid() again and again.

It is crazy to repeat set and unset of internal flags. However, we
cannot simply get rid of "sym-&gt;flags &amp;= flags | ~SYMBOL_DEF_USER;"
Doing so would re-introduce the problem solved by commit 5d09598d488f
("kconfig: fix new choices being skipped upon config update").

To work around the issue, conf_write_autoconf() stopped calling
sym_clear_all_valid().

conf_write() must be changed accordingly. Currently, it clears
SYMBOL_WRITE after the symbol is written into the .config file. This
is needed to prevent it from writing the same symbol multiple times in
case the symbol is declared in two or more locations. I added the new
flag SYMBOL_WRITTEN, to track the symbols that have been written.

Anyway, this is a cheesy workaround in order to suppress the issue
as far as defconfig is concerned.

Handling of choices is totally broken. sym_clear_all_valid() is called
every time a user touches a symbol from the GUI interface. To reproduce
it, just add a new symbol drivers/usb/gadget/legacy/Kconfig, then touch
around unrelated symbols from menuconfig. USB_FUNCTIONFS will disappear
from the .config file.

I added the Fixes tag since it is more fatal than before. But, this
has been broken since long long time before, and still it is.
We should take a closer look to fix this correctly somehow.

Fixes: 00c864f8903d ("kconfig: allow all config targets to write auto.conf if missing")
Cc: linux-stable &lt;stable@vger.kernel.org&gt; # 4.19+
Reported-by: Joonas Kylmälä &lt;joonas.kylmala@iki.fi&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Tested-by: Joonas Kylmälä &lt;joonas.kylmala@iki.fi&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>kconfig: remove P_ENV property type</title>
<updated>2018-08-14T00:01:47Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2018-08-13T16:48:39Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=1880861226c13ddd42c34ddd30c3b502b650fe29'/>
<id>urn:sha1:1880861226c13ddd42c34ddd30c3b502b650fe29</id>
<content type='text'>
This property is not set by anyone since commit 104daea149c4 ("kconfig:
reference environment variables directly and remove 'option env='").

Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Acked-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
</content>
</entry>
<entry>
<title>kconfig: rename SYMBOL_AUTO to SYMBOL_NO_WRITE</title>
<updated>2018-07-17T16:18:09Z</updated>
<author>
<name>Dirk Gouders</name>
<email>dirk@gouders.net</email>
</author>
<published>2018-07-03T12:43:31Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=693359f7ac9012778590a370d076b13db704255e'/>
<id>urn:sha1:693359f7ac9012778590a370d076b13db704255e</id>
<content type='text'>
Over time, the use of the flag SYMBOL_AUTO changed from initially
marking three automatically generated symbols ARCH, KERNELRELEASE and
UNAME_RELEASE to today's effect of protecting symbols from being
written out.

Currently, only symbols of type CHOICE and those with option
defconf_list set have that flag set.

Reflect that change in semantics in the flag's name.

Signed-off-by: Dirk Gouders &lt;dirk@gouders.net&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kconfig: handle P_SYMBOL in print_symbol()</title>
<updated>2018-06-28T13:47:47Z</updated>
<author>
<name>Dirk Gouders</name>
<email>dirk@gouders.net</email>
</author>
<published>2018-06-22T19:27:38Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=ecd53ac2f2c6e42fe732d0aa282192cb6ad3faea'/>
<id>urn:sha1:ecd53ac2f2c6e42fe732d0aa282192cb6ad3faea</id>
<content type='text'>
Each symbol has a property of type P_SYMBOL since commit
59e89e3ddf85 (kconfig: save location of config symbols).
Handle those properties in print_symbol().

Further, place a pointer to print_symbol() in the comment above the
list of known property type.

Signed-off-by: Dirk Gouders &lt;dirk@gouders.net&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kconfig: make unmet dependency warnings readable</title>
<updated>2018-03-25T17:04:06Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2018-03-13T09:56:08Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=f8f69dc0b4e070d4a4d39889a85424913cc922d5'/>
<id>urn:sha1:f8f69dc0b4e070d4a4d39889a85424913cc922d5</id>
<content type='text'>
Currently, the unmet dependency warnings end up with endlessly long
expressions, most of which are false positives.

Here is test code to demonstrate how it currently works.

[Test Case]

  config DEP1
          def_bool y

  config DEP2
          bool "DEP2"

  config A
          bool "A"
          select E

  config B
          bool "B"
          depends on DEP2
          select E

  config C
          bool "C"
          depends on DEP1 &amp;&amp; DEP2
          select E

  config D
          def_bool n
          select E

  config E
          bool
          depends on DEP1 &amp;&amp; DEP2

[Result]

  $ make config
  scripts/kconfig/conf  --oldaskconfig Kconfig
  *
  * Linux Kernel Configuration
  *
  DEP2 (DEP2) [N/y/?] (NEW) n
  A (A) [N/y/?] (NEW) y
  warning: (A &amp;&amp; B &amp;&amp; D) selects E which has unmet direct
  dependencies (DEP1 &amp;&amp; DEP2)

Here, I see some points to be improved.

First, '(A || B || D)' would make more sense than '(A &amp;&amp; B &amp;&amp; D)'.
I am not sure if this is intentional, but expr_simplify_unmet_dep()
turns OR expressions into AND, like follows:

        case E_OR:
                return expr_alloc_and(

Second, we see false positives.  'A' is a real unmet dependency.
'B' is false positive because 'DEP1' is fixed to 'y', and 'B' depends
on 'DEP2'.  'C' was correctly dropped by expr_simplify_unmet_dep().
'D' is also false positive because it has no chance to be enabled.
Current expr_simplify_unmet_dep() cannot avoid those false positives.

After all, I decided to use the same helpers as used for printing
reverse dependencies in the help.

With this commit, unreadable warnings (most of the reported symbols are
false positives) in the real world:

$ make ARCH=score allyesconfig
scripts/kconfig/conf  --allyesconfig Kconfig
warning: (HWSPINLOCK_QCOM &amp;&amp; AHCI_MTK &amp;&amp; STMMAC_PLATFORM &amp;&amp;
 DWMAC_IPQ806X &amp;&amp; DWMAC_LPC18XX &amp;&amp; DWMAC_OXNAS &amp;&amp; DWMAC_ROCKCHIP &amp;&amp;
 DWMAC_SOCFPGA &amp;&amp; DWMAC_STI &amp;&amp; TI_CPSW &amp;&amp; PINCTRL_GEMINI &amp;&amp;
 PINCTRL_OXNAS &amp;&amp; PINCTRL_ROCKCHIP &amp;&amp; PINCTRL_DOVE &amp;&amp;
 PINCTRL_ARMADA_37XX &amp;&amp; PINCTRL_STM32 &amp;&amp; S3C2410_WATCHDOG &amp;&amp;
 VIDEO_OMAP3 &amp;&amp; VIDEO_S5P_FIMC &amp;&amp; USB_XHCI_MTK &amp;&amp; RTC_DRV_AT91SAM9 &amp;&amp;
 LPC18XX_DMAMUX &amp;&amp; VIDEO_OMAP4 &amp;&amp; COMMON_CLK_GEMINI &amp;&amp;
 COMMON_CLK_ASPEED &amp;&amp; COMMON_CLK_NXP &amp;&amp; COMMON_CLK_OXNAS &amp;&amp;
 COMMON_CLK_BOSTON &amp;&amp; QCOM_ADSP_PIL &amp;&amp; QCOM_Q6V5_PIL &amp;&amp; QCOM_GSBI &amp;&amp;
 ATMEL_EBI &amp;&amp; ST_IRQCHIP &amp;&amp; RESET_IMX7 &amp;&amp; PHY_HI6220_USB &amp;&amp;
 PHY_RALINK_USB &amp;&amp; PHY_ROCKCHIP_PCIE &amp;&amp; PHY_DA8XX_USB) selects
 MFD_SYSCON which has unmet direct dependencies (HAS_IOMEM)
warning: (PINCTRL_AT91 &amp;&amp; PINCTRL_AT91PIO4 &amp;&amp; PINCTRL_OXNAS &amp;&amp;
 PINCTRL_PISTACHIO &amp;&amp; PINCTRL_PIC32 &amp;&amp; PINCTRL_MESON &amp;&amp;
 PINCTRL_NOMADIK &amp;&amp; PINCTRL_MTK &amp;&amp; PINCTRL_MT7622 &amp;&amp; GPIO_TB10X)
 selects OF_GPIO which has unmet direct dependencies (GPIOLIB &amp;&amp; OF &amp;&amp;
 HAS_IOMEM)
warning: (FAULT_INJECTION_STACKTRACE_FILTER &amp;&amp; LATENCYTOP &amp;&amp; LOCKDEP)
 selects FRAME_POINTER which has unmet direct dependencies
 (DEBUG_KERNEL &amp;&amp; (CRIS || M68K || FRV || UML || SUPERH || BLACKFIN ||
 MN10300 || METAG) || ARCH_WANT_FRAME_POINTERS)

will be turned into:

$ make ARCH=score allyesconfig
scripts/kconfig/conf  --allyesconfig Kconfig

WARNING: unmet direct dependencies detected for MFD_SYSCON
  Depends on [n]: HAS_IOMEM [=n]
  Selected by [y]:
  - PINCTRL_STM32 [=y] &amp;&amp; PINCTRL [=y] &amp;&amp; (ARCH_STM32 ||
 COMPILE_TEST [=y]) &amp;&amp; OF [=y]
  - RTC_DRV_AT91SAM9 [=y] &amp;&amp; RTC_CLASS [=y] &amp;&amp; (ARCH_AT91 ||
 COMPILE_TEST [=y])
  - RESET_IMX7 [=y] &amp;&amp; RESET_CONTROLLER [=y]
  - PHY_HI6220_USB [=y] &amp;&amp; (ARCH_HISI &amp;&amp; ARM64 ||
 COMPILE_TEST [=y])
  - PHY_RALINK_USB [=y] &amp;&amp; (RALINK || COMPILE_TEST [=y])
  - PHY_ROCKCHIP_PCIE [=y] &amp;&amp; (ARCH_ROCKCHIP &amp;&amp; OF [=y] ||
 COMPILE_TEST [=y])

WARNING: unmet direct dependencies detected for OF_GPIO
  Depends on [n]: GPIOLIB [=y] &amp;&amp; OF [=y] &amp;&amp; HAS_IOMEM [=n]
  Selected by [y]:
  - PINCTRL_MTK [=y] &amp;&amp; PINCTRL [=y] &amp;&amp; (ARCH_MEDIATEK ||
 COMPILE_TEST [=y]) &amp;&amp; OF [=y]
  - PINCTRL_MT7622 [=y] &amp;&amp; PINCTRL [=y] &amp;&amp; (ARCH_MEDIATEK ||
 COMPILE_TEST [=y]) &amp;&amp; OF [=y] &amp;&amp; (ARM64 || COMPILE_TEST [=y])

WARNING: unmet direct dependencies detected for FRAME_POINTER
  Depends on [n]: DEBUG_KERNEL [=y] &amp;&amp; (CRIS || M68K || FRV || UML ||
 SUPERH || BLACKFIN || MN10300 || METAG) || ARCH_WANT_FRAME_POINTERS [=n]
  Selected by [y]:
  - LATENCYTOP [=y] &amp;&amp; DEBUG_KERNEL [=y] &amp;&amp; STACKTRACE_SUPPORT [=y] &amp;&amp;
 PROC_FS [=y] &amp;&amp; !MIPS &amp;&amp; !PPC &amp;&amp; !S390 &amp;&amp; !MICROBLAZE &amp;&amp; !ARM_UNWIND &amp;&amp;
 !ARC &amp;&amp; !X86

Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Reviewed-by: Petr Vorel &lt;petr.vorel@gmail.com&gt;
</content>
</entry>
<entry>
<title>kconfig: Print reverse dependencies in groups</title>
<updated>2018-03-25T17:03:58Z</updated>
<author>
<name>Eugeniu Rosca</name>
<email>erosca@de.adit-jv.com</email>
</author>
<published>2018-02-24T15:24:18Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=d9119b5925a03b9a3191fa3e93b4091651d8ad25'/>
<id>urn:sha1:d9119b5925a03b9a3191fa3e93b4091651d8ad25</id>
<content type='text'>
Surprisingly or not, disabling a CONFIG option (which is assumed to
be unneeded) may be not so trivial. Especially it is not trivial, when
this CONFIG option is selected by a dozen of other configs. Before the
moment commit 1ccb27143360 ("kconfig: make "Selected by:" and
"Implied by:" readable") popped up in v4.16-rc1, it was an absolute pain
to break down the "Selected by" reverse dependency expression in order
to identify all those configs which select (IOW *do not allow
disabling*) a certain feature (assumed to be not needed).

This patch tries to make one step further by putting at users'
fingertips the revdep top level OR sub-expressions grouped/clustered by
the tristate value they evaluate to. This should allow the users to
directly concentrate on and tackle the _active_ reverse dependencies.

To give some numbers and quantify the complexity of certain reverse
dependencies, assuming commit 617aebe6a97e ("Merge tag
'usercopy-v4.16-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux"), ARCH=arm64
and vanilla arm64 defconfig, here is the top 10 CONFIG options with
the highest amount of top level "||" sub-expressions/tokens that make
up the final "Selected by" reverse dependency expression.

| Config            | All revdep | Active revdep |
|-------------------|------------|---------------|
| REGMAP_I2C        | 212        | 9             |
| CRC32             | 167        | 25            |
| FW_LOADER         | 128        | 5             |
| MFD_CORE          | 124        | 9             |
| FB_CFB_IMAGEBLIT  | 114        | 2             |
| FB_CFB_COPYAREA   | 111        | 2             |
| FB_CFB_FILLRECT   | 110        | 2             |
| SND_PCM           | 103        | 2             |
| CRYPTO_HASH       | 87         | 19            |
| WATCHDOG_CORE     | 86         | 6             |

The story behind the above is that users need to visually
review/evaluate 212 expressions which *potentially* select REGMAP_I2C
in order to identify the expressions which *actually* select REGMAP_I2C,
for a particular ARCH and for a particular defconfig used.

To make this experience smoother, change the way reverse dependencies
are displayed to the user from [1] to [2].

[1] Old representation of DMA_ENGINE_RAID:
  Selected by:
  - AMCC_PPC440SPE_ADMA [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; (440SPe || 440SP)
  - BCM_SBA_RAID [=m] &amp;&amp; DMADEVICES [=y] &amp;&amp; (ARM64 [=y] || ...
  - FSL_RAID [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; FSL_SOC &amp;&amp; ...
  - INTEL_IOATDMA [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; PCI [=y] &amp;&amp; X86_64
  - MV_XOR [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; (PLAT_ORION || ARCH_MVEBU [=y] ...
  - MV_XOR_V2 [=y] &amp;&amp; DMADEVICES [=y] &amp;&amp; ARM64 [=y]
  - XGENE_DMA [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; (ARCH_XGENE [=y] || ...
  - DMATEST [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; DMA_ENGINE [=y]

[2] New representation of DMA_ENGINE_RAID:
  Selected by [y]:
  - MV_XOR_V2 [=y] &amp;&amp; DMADEVICES [=y] &amp;&amp; ARM64 [=y]
  Selected by [m]:
  - BCM_SBA_RAID [=m] &amp;&amp; DMADEVICES [=y] &amp;&amp; (ARM64 [=y] || ...
  Selected by [n]:
  - AMCC_PPC440SPE_ADMA [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; (440SPe || ...
  - FSL_RAID [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; FSL_SOC &amp;&amp; ...
  - INTEL_IOATDMA [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; PCI [=y] &amp;&amp; X86_64
  - MV_XOR [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; (PLAT_ORION || ARCH_MVEBU [=y] ...
  - XGENE_DMA [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; (ARCH_XGENE [=y] || ...
  - DMATEST [=n] &amp;&amp; DMADEVICES [=y] &amp;&amp; DMA_ENGINE [=y]

Suggested-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Signed-off-by: Eugeniu Rosca &lt;erosca@de.adit-jv.com&gt;
Reviewed-by: Petr Vorel &lt;pvorel@suse.cz&gt;
Reviewed-by: Ulf Magnusson &lt;ulfalizer@gmail.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kconfig: make "Selected by:" and "Implied by:" readable</title>
<updated>2018-01-25T12:53:00Z</updated>
<author>
<name>Petr Vorel</name>
<email>petr.vorel@gmail.com</email>
</author>
<published>2018-01-25T09:46:35Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=1ccb27143360bd2390a9a970e50709f858b53761'/>
<id>urn:sha1:1ccb27143360bd2390a9a970e50709f858b53761</id>
<content type='text'>
Reverse dependency expressions can get rather unwieldy, especially if
a symbol is selected by more than a handful of other symbols. I.e. it's
possible to have near endless expressions like:
   A &amp;&amp; B &amp;&amp; !C || D || F &amp;&amp; (G || H) || [...]

Chop these expressions into actually readable chunks:
   - A &amp;&amp; B &amp;&amp; !C
   - D
   - F &amp;&amp; (G || H)
   - [...]

I.e. transform the top level OR tokens into newlines and prepend each
line with a minus. This makes the "Selected by:" and "Implied by:" blurb
much easier to read. This is done only if there is more than one top
level OR. "Depends on:" and "Range :" were deliberately left as they are.

Based on idea from Paul Bolle.

Suggested-by: Paul Bolle &lt;pebolle@tiscali.nl&gt;
Signed-off-by: Petr Vorel &lt;petr.vorel@gmail.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kconfig: Document the 'symbol' struct</title>
<updated>2017-12-07T14:46:57Z</updated>
<author>
<name>Ulf Magnusson</name>
<email>ulfalizer@gmail.com</email>
</author>
<published>2017-10-04T05:48:14Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=52aede4ba5efd159a6c5f4a0c25586cb26e7befc'/>
<id>urn:sha1:52aede4ba5efd159a6c5f4a0c25586cb26e7befc</id>
<content type='text'>
Visibility and choices in particular might be a bit tricky to figure
out.

Also fix existing comment to point out that P_MENU is also used for
menus.

Signed-off-by: Ulf Magnusson &lt;ulfalizer@gmail.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kconfig: Document the 'menu' struct</title>
<updated>2017-12-07T14:46:16Z</updated>
<author>
<name>Ulf Magnusson</name>
<email>ulfalizer@gmail.com</email>
</author>
<published>2017-10-04T03:37:12Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=33ca1a24866373777c5e1415f974069835f8cf41'/>
<id>urn:sha1:33ca1a24866373777c5e1415f974069835f8cf41</id>
<content type='text'>
Understanding what it represents helps a lot when reading the code, and
it's not obvious, so document it.

The ROOT_MENU flag is only set and tested by the gconf and qconf front
ends, so leave it undocumented here. The obvious guess for what it means
is correct.

Signed-off-by: Ulf Magnusson &lt;ulfalizer@gmail.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>Kconfig: Introduce the "imply" keyword</title>
<updated>2016-11-16T08:26:33Z</updated>
<author>
<name>Nicolas Pitre</name>
<email>nicolas.pitre@linaro.org</email>
</author>
<published>2016-11-11T05:10:05Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=237e3ad0f195d8fd34f1299e45f04793832a16fc'/>
<id>urn:sha1:237e3ad0f195d8fd34f1299e45f04793832a16fc</id>
<content type='text'>
The "imply" keyword is a weak version of "select" where the target
config symbol can still be turned off, avoiding those pitfalls that come
with the "select" keyword.

This is useful e.g. with multiple drivers that want to indicate their
ability to hook into a secondary subsystem while allowing the user to
configure that subsystem out without also having to unset these drivers.

Currently, the same effect can almost be achieved with:

config DRIVER_A
	tristate

config DRIVER_B
	tristate

config DRIVER_C
	tristate

config DRIVER_D
	tristate

[...]

config SUBSYSTEM_X
	tristate
	default DRIVER_A || DRIVER_B || DRIVER_C || DRIVER_D || [...]

This is unwieldy to maintain especially with a large number of drivers.
Furthermore, there is no easy way to restrict the choice for SUBSYSTEM_X
to y or n, excluding m, when some drivers are built-in. The "select"
keyword allows for excluding m, but it excludes n as well. Hence
this "imply" keyword.  The above becomes:

config DRIVER_A
	tristate
	imply SUBSYSTEM_X

config DRIVER_B
	tristate
	imply SUBSYSTEM_X

[...]

config SUBSYSTEM_X
	tristate

This is much cleaner, and way more flexible than "select". SUBSYSTEM_X
can still be configured out, and it can be set as a module when none of
the drivers are configured in or all of them are modular.

Signed-off-by: Nicolas Pitre &lt;nico@linaro.org&gt;
Acked-by: Richard Cochran &lt;richardcochran@gmail.com&gt;
Acked-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: John Stultz &lt;john.stultz@linaro.org&gt;
Reviewed-by: Josh Triplett &lt;josh@joshtriplett.org&gt;
Cc: Paul Bolle &lt;pebolle@tiscali.nl&gt;
Cc: linux-kbuild@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: Michal Marek &lt;mmarek@suse.com&gt;
Cc: Edward Cree &lt;ecree@solarflare.com&gt;
Link: http://lkml.kernel.org/r/1478841010-28605-2-git-send-email-nicolas.pitre@linaro.org
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

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