[PATCH] drm/efidrm: ensure screen_base is initialized

[Arnd Bergmann]

From: Arnd Bergmann <a...@arndb.de>

clang points out that there is a code path that leads to undefined behavior:

drivers/gpu/drm/sysfb/efidrm.c:353:11: error: variable 'screen_base' is used 
uninitialized whenever 'if' condition is false 
[-Werror,-Wsometimes-uninitialized]
  353 |         else if (mem_flags & EFI_MEMORY_WB)
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~

Add the missing initialization.

Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
 drivers/gpu/drm/sysfb/efidrm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/sysfb/efidrm.c b/drivers/gpu/drm/sysfb/efidrm.c
index af90064a4c04..85fc37c1e87a 100644
--- a/drivers/gpu/drm/sysfb/efidrm.c
+++ b/drivers/gpu/drm/sysfb/efidrm.c
@@ -353,6 +353,9 @@ static struct efidrm_device *efidrm_device_create(struct 
drm_driver *drv,
        else if (mem_flags & EFI_MEMORY_WB)
                screen_base = devm_memremap(&pdev->dev, mem->start, 
resource_size(mem),
                                            MEMREMAP_WB);
+       else
+               screen_base = NULL;
+
        if (!screen_base)
                return ERR_PTR(-ENOMEM);
        iosys_map_set_vaddr_iomem(&sysfb->fb_addr, screen_base);
-- 
2.39.5