drm: Fix build error caused by missing drm_nomodeset.o

The patch for commit 6a2d2ddf2c34 ("drm: Move nomodeset kernel parameter
to the DRM subsystem") was generated with config 'diff.noprefix true'.

But later was applied using 'cat nomodeset.mbox | dim apply-branch' on a
machine with 'diff.noprefix false'. And command 'git am --scissors -3' as
used by the dim tool doesn't handle that case well, since the 3-way merge
wrongly resolves the path for new file drivers/gpu/drm/drm_nomodeset.c as
gpu/drm/drm_nomodeset.c instead.

It led to the following build error as reported by the kernel test robot:

  make[4]: *** No rule to make target 'drivers/gpu/drm/drm_nomodeset.o', needed by 'drivers/gpu/drm/built-in.a'.

Fixes: 6a2d2ddf2c34 ("drm: Move nomodeset kernel parameter to the DRM subsystem")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211127191910.709356-1-javierm@redhat.com

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_nomodeset.c b/drivers/gpu/drm/drm_nomodeset.c
new file mode 100644
index 000000000000..f3978d5bd3a1
--- /dev/null
+++ b/drivers/gpu/drm/drm_nomodeset.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+static bool drm_nomodeset;
+
+bool drm_firmware_drivers_only(void)
+{
+	return drm_nomodeset;
+}
+EXPORT_SYMBOL(drm_firmware_drivers_only);
+
+static int __init disable_modeset(char *str)
+{
+	drm_nomodeset = true;
+
+	pr_warn("Booted with the nomodeset parameter. Only the system framebuffer will be available\n");
+
+	return 1;
+}
+
+/* Disable kernel modesetting */
+__setup("nomodeset", disable_modeset);