[PATCH] drm: fb_helper: improve CONFIG_FB dependency

[PATCH] drm: fb_helper: improve CONFIG_FB dependency

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

My previous patch correctly addressed the possible link failure, but as
Jani points out, the dependency is now stricter than it needs to be.

Change it again, to allow DRM_FBDEV_EMULATION to be used when
DRM_KMS_HELPER and FB are both loadable modules and DRM is linked into
the kernel.

As a side-effect, the option is now only visible when at least one DRM
driver makes use of DRM_KMS_HELPER. This is better, because the option
has no effect otherwise.

Fixes: 606b102876e3 ("drm: fb_helper: fix CONFIG_FB dependency")
Suggested-by: Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/Kconfig | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index c08860db2520..d2e6d8ce5000 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -117,9 +117,8 @@ config DRM_DEBUG_MODESET_LOCK
 
 config DRM_FBDEV_EMULATION
 	bool "Enable legacy fbdev support for your modesetting driver"
-	depends on DRM
-	depends on FB=y || FB=DRM
-	select DRM_KMS_HELPER
+	depends on DRM_KMS_HELPER
+	depends on FB=y || FB=DRM_KMS_HELPER
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
 	select FB_CFB_IMAGEBLIT
-- 
2.29.2

Re: [PATCH] drm: fb_helper: improve CONFIG_FB dependency

[Daniel Vetter]

On Fri, Oct 29, 2021 at 02:02:38PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> My previous patch correctly addressed the possible link failure, but as
> Jani points out, the dependency is now stricter than it needs to be.
> 
> Change it again, to allow DRM_FBDEV_EMULATION to be used when
> DRM_KMS_HELPER and FB are both loadable modules and DRM is linked into
> the kernel.
> 
> As a side-effect, the option is now only visible when at least one DRM
> driver makes use of DRM_KMS_HELPER. This is better, because the option
> has no effect otherwise.
> 
> Fixes: 606b102876e3 ("drm: fb_helper: fix CONFIG_FB dependency")
> Suggested-by: Acked-by: Jani Nikula <jani.nikula@intel.com>
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Queued up for the merge window, thanks for the patch.
-Daniel

> ---
>  drivers/gpu/drm/Kconfig | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index c08860db2520..d2e6d8ce5000 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -117,9 +117,8 @@ config DRM_DEBUG_MODESET_LOCK
>  
>  config DRM_FBDEV_EMULATION
>  	bool "Enable legacy fbdev support for your modesetting driver"
> -	depends on DRM
> -	depends on FB=y || FB=DRM
> -	select DRM_KMS_HELPER
> +	depends on DRM_KMS_HELPER
> +	depends on FB=y || FB=DRM_KMS_HELPER
>  	select FB_CFB_FILLRECT
>  	select FB_CFB_COPYAREA
>  	select FB_CFB_IMAGEBLIT
> -- 
> 2.29.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch