[PATCH 1/2] drm/panel: remove unnecessary dependencies

On Thu, Jun 12, 2014 at 06:00:07PM +0200, Arnd Bergmann wrote:

On Thursday 12 June 2014 16:50:15 Russell King wrote:

quoted

DRM_PANEL_LD9040 and DRM_PANEL_S6E8AA0 both explicitly depended on
DRM_PANEL && DRM.  This is nonsense for two reasons:

(a) DRM_PANEL already depends on DRM, so DRM_PANEL can not be enabled
without DRM first being enabled.  Hence the && DRM is useless.

(b) These two configs are already beneath a menu which depends on
DRM_PANEL being enabled; these options will not be visible without
DRM_PANEL already being enabled.

Let's just remove this unnecessary verbosity.

Signed-off-by: Russell King <redacted>

Unfortunately, this is wrong, because the current expression
exploits one of the finer details of Kconfig syntax:

quoted

 drivers/gpu/drm/panel/Kconfig | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 4ec874da5668..44aea730b3aa 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig

@@ -18,14 +18,12 @@ config DRM_PANEL_SIMPLE
 
 config DRM_PANEL_LD9040
        tristate "LD9040 RGB/SPI panel"
-       depends on DRM && DRM_PANEL
        depends on OF
        select SPI
        select VIDEOMODE_HELPERS
 
 config DRM_PANEL_S6E8AA0
        tristate "S6E8AA0 DSI video mode panel"
-       depends on DRM && DRM_PANEL
        depends on OF
        select DRM_MIPI_DSI
        select VIDEOMODE_HELPERS

DRM_PANEL is bool, while DRM is tristate. If DRM=m and DRM_PANEL=y,
these two options can only be 'n' or 'm' but not 'y' with the current
code, but they can be 'y' if you drop the explicit DRM dependency,
which will cause a link failure.

The DRM_PANEL dependency can be removed, it is indeed unnecessary.

In which case, that's a bug for DRM_PANEL_SIMPLE which uses the same
mechanism.  Since everything is going to be in the same boat, the
menu should depend on DRM && DRM_PANEL.

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