Hi Greg,
On 10/9/24 06:56, Greg Kroah-Hartman wrote:
On Sat, Sep 21, 2024 at 03:06:09PM -0300, Fabricio Gasperin wrote:
Fixes the following compilation error:
ERROR: modpost: "fb_io_read" [drivers/staging/sm750fb/sm750fb.ko] undefined!
ERROR: modpost: "fb_io_write" [drivers/staging/sm750fb/sm750fb.ko] undefined!
ERROR: modpost: "fb_io_mmap" [drivers/staging/sm750fb/sm750fb.ko] undefined!
Signed-off-by: Fabricio Gasperin <fgasperin@xxxxxxxxxx>
---
drivers/staging/sm750fb/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/staging/sm750fb/Kconfig b/drivers/staging/sm750fb/Kconfig
index 08bcccdd0f1c..eca1aa43d725 100644
--- a/drivers/staging/sm750fb/Kconfig
+++ b/drivers/staging/sm750fb/Kconfig
@@ -3,6 +3,7 @@ config FB_SM750
tristate "Silicon Motion SM750 framebuffer support"
depends on FB && PCI && HAS_IOPORT
select FB_MODE_HELPERS
+ select FB_IOMEM_FOPS
select FB_CFB_FILLRECT
select FB_CFB_COPYAREA
select FB_CFB_IMAGEBLIT
--
2.46.1
What is causing this error? What commit created the problem, and why
has no one reported it yet?
This happens because drivers/staging/sm750fb/sm750.c, defines an fb_ops
structure:
static const struct fb_ops lynxfb_ops = {
.owner = THIS_MODULE,
FB_DEFAULT_IOMEM_OPS,
...
};
FB_DEFAULT_IOMEM_OPS expands to the fb_io_* helpers declared in
include/linux/fb.h and defined in drivers/video/fbdev/core/fb_io_fops.c;
however, the latter is gated by FB_IOMEM_FOPS, so when compiling a
kernel with CONFIG_STAGING=y + CONFIG_FB=m + CONFIG_FB_SM750=m, you get
the following error:
ERROR: modpost: "fb_io_read" [drivers/staging/sm750fb/sm750fb.ko] undefined!
ERROR: modpost: "fb_io_write" [drivers/staging/sm750fb/sm750fb.ko]
undefined!
ERROR: modpost: "fb_io_mmap" [drivers/staging/sm750fb/sm750fb.ko] undefined!
make[2]: *** [scripts/Makefile.modpost:145: Module.symvers] Error 1
So in order to solve it we select FB_IOMEM_FOPS, much like the other
FB_* drivers do in drivers/video/fbdev/Kconfig.
Not entirely sure why this wasn't caught before, but the commit that
broke the build for sm750fb is 6b180f66c0dd ("fbdev: Provide I/O-memory
helpers as module"), which made the fb_io_* helpers be built as a
separate module instead of being bundled in fb.o (which is what sm750fb
was relying on). I think Fabricio can add a "Fixes:" tag in v2.
Thanks,
Vinicius
confused,
greg k-h
