Staging: udlfb: explicit dependencies and warnings
Specify Kconfig dependencies, and include warnings for building as a module
udlfb is dependent on FB_DEFERRED_IO, FB_SYS_*, and FB_MODE_HELPERS
Because many kernels do not include defio (which cannot be built
as a module), yet users want to be able to build udlfb as a module later,
udlfb has ifdefs and these dependency warnings to help udlfb build with or
without certain dependencies, but also print warnings for any lost function.
Even though this kind of flexibility isn't common, we've gotten feedback
from a significant portion of users that they were frustrated without it.
Signed-off-by: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/udlfb/udlfb.c b/drivers/staging/udlfb/udlfb.c
index 939b8fa..baad03a 100644
--- a/drivers/staging/udlfb/udlfb.c
+++ b/drivers/staging/udlfb/udlfb.c
@@ -56,6 +56,20 @@
};
MODULE_DEVICE_TABLE(usb, id_table);
+#ifndef CONFIG_FB_DEFERRED_IO
+#warning message "kernel FB_DEFFERRED_IO option to support generic fbdev apps"
+#endif
+
+#ifndef CONFIG_FB_SYS_IMAGEBLIT
+#ifndef CONFIG_FB_SYS_IMAGEBLIT_MODULE
+#warning message "FB_SYS_* in kernel or module option to support fb console"
+#endif
+#endif
+
+#ifndef CONFIG_FB_MODE_HELPERS
+#warning message "kernel FB_MODE_HELPERS required. Expect build break"
+#endif
+
/* dlfb keeps a list of urbs for efficient bulk transfers */
static void dlfb_urb_completion(struct urb *urb);
static struct urb *dlfb_get_urb(struct dlfb_data *dev);