Messages in this thread | | | Date | Wed, 7 Apr 2010 22:29:37 +0200 | From | Bruno Prémont <> | Subject | Re: [PATCH mmotm] hid-picolcd: depends on LCD_CLASS_DEVICE |
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On Wed, 07 April 2010 Randy Dunlap <randy.dunlap@oracle.com> wrote: > On Wed, 7 Apr 2010 20:44:04 +0200 Bruno Prémont wrote: > > > On Tue, 06 April 2010 Randy Dunlap <randy.dunlap@oracle.com> wrote: > > > > > > > > One of my attempts did end up with a circular loop with regard to FB > > > > (some of the FB drivers did select INPUT)? > > > > > > (not that I can find) > > > > > > CONFIG_VT does select INPUT > > > and CONFIG_DRM_I915 does > > > select INPUT if ACPI > > > > A newer attempt still produces the same result: > > > > drivers/input/Kconfig:9:error: found recursive dependency: INPUT -> > > HID_SUPPORT -> HID_PICOLCD_FB -> FB -> FB_STI -> VT -> INPUT > > > > (it's only FB which causes the loop, LEDS, LCD and BACKLIGHT are fine) > > (yes, so I see) > > > This is with following patch on top of the improved deps patch I sent > > a few minutes ago deeper in this thread. > > > > Is there a way around this? > > > > Well, lesson #1 is that select is evil^W^W should only be used to enable > library-like code, or as Documentation/kbuild/kconfig-language.txt says: > > Note: > select should be used with care. select will force > a symbol to a value without visiting the dependencies. > By abusing select you are able to select a symbol FOO even > if FOO depends on BAR that is not set. > In general use select only for non-visible symbols > (no prompts anywhere) and for symbols with no dependencies. > That will limit the usefulness but on the other hand avoid > the illegal configurations all over. > kconfig should one day warn about such things.
I've read that paragraph and I would definitely prefer not to have to use select for what this patch should achieve!
It should really be a helper for the user going through menuconfig like "please check all what is needed to satisfy this item's dependencies" A "try-select-deep" or whatever it could be called.
A well-behaved "GUI" implementation of this would show what would get newly checked and give the user the opportunity to not proceed or fine-tune y/m choices.
> (more below) > > > > > diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig > > index 782a34e..711c091 100644 > > --- a/drivers/hid/Kconfig > > +++ b/drivers/hid/Kconfig > > @@ -285,7 +285,7 @@ config HID_PICOLCD_FB > > bool "Framebuffer support" > > default !EMBEDDED > > depends on HID_PICOLCD > > - depends on HID_PICOLCD=FB || FB=y > > + select FB > > If you'll go back to the unpatched (by this patch) version here, > it seems to work OK.
So best is probably to just forget about all of this non-leaf select usage for now. (and not have one half doing one way and the other half doing it the other way)
Thanks, Bruno
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