| Message ID | 20210721151839.2484245-1-arnd@kernel.org |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | fbdev: simplefb: fix Kconfig dependencies | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | warning | total: 0 errors, 2 warnings, 18 lines checked |
On Wed, Jul 21, 2021 at 9:18 AM Arnd Bergmann <arnd@kernel.org> wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > Configurations with both CONFIG_FB_SIMPLE=y and CONFIG_DRM_SIMPLEDRM=m > are allowed by Kconfig because the 'depends on !DRM_SIMPLEDRM' dependency > does not disallow FB_SIMPLE as long as SIMPLEDRM is not built-in. This Double negative. How about: allows FB_SIMPLE as long as SIMPLEDRM is not built-in. > can however result in a build failure when cfb_fillrect() etc are then > also in loadable modules: > > x86_64-linux-ld: drivers/video/fbdev/simplefb.o:(.rodata+0x1f8): undefined reference to `cfb_fillrect' > x86_64-linux-ld: drivers/video/fbdev/simplefb.o:(.rodata+0x200): undefined reference to `cfb_copyarea' > x86_64-linux-ld: drivers/video/fbdev/simplefb.o:(.rodata+0x208): undefined reference to `cfb_imageblit' > > To work around this, change FB_SIMPLE to be a 'tristate' symbol, > which still allows both to be =m together, but not one of them to > be =y if the other one is =m. If a distro kernel picks this > configuration, it can be determined by local policy which of > the two modules gets loaded. The 'of_chosen' export is needed > as this is the first loadable module referencing it. > > Alternatively, the Kconfig dependency could be changed to > 'depends on DRM_SIMPLEDRM=n', which would forbid the configuration > with both drivers. > > Fixes: 11e8f5fd223b ("drm: Add simpledrm driver") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/of/base.c | 1 + > drivers/video/fbdev/Kconfig | 5 +++-- > 2 files changed, 4 insertions(+), 2 deletions(-) For the DT change: Acked-by: Rob Herring <robh@kernel.org>
diff --git a/drivers/of/base.c b/drivers/of/base.c index 48e941f99558..073ea7cd007b 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -36,6 +36,7 @@ LIST_HEAD(aliases_lookup); struct device_node *of_root; EXPORT_SYMBOL(of_root); struct device_node *of_chosen; +EXPORT_SYMBOL(of_chosen); struct device_node *of_aliases; struct device_node *of_stdout; static const char *of_stdout_options; diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig index 8a98539ec490..5fbcb3cc2e8e 100644 --- a/drivers/video/fbdev/Kconfig +++ b/drivers/video/fbdev/Kconfig @@ -2207,8 +2207,9 @@ config FB_HYPERV This framebuffer driver supports Microsoft Hyper-V Synthetic Video. config FB_SIMPLE - bool "Simple framebuffer support" - depends on (FB = y) && !DRM_SIMPLEDRM + tristate "Simple framebuffer support" + depends on FB + depends on !DRM_SIMPLEDRM select FB_CFB_FILLRECT select FB_CFB_COPYAREA select FB_CFB_IMAGEBLIT