Move the nomodeset kernel parameter to drivers/video to make it
available to non-DRM drivers. Adapt the interface, but keep the DRM
interface drm_firmware_drivers_only() to avoid churn within DRM. The
function should later be inlined into callers.
The parameter disables any DRM graphics driver that would replace a
driver for firmware-provided scanout buffers. It is an option to easily
fallback to basic graphics output if the hardware's native driver is
broken. Moving it to a more prominent location wil make it available
to fbdev as well.
v2:
* clarify the meaning of the nomodeset parameter (Javier)
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 15 +++++++++------
MAINTAINERS | 2 ++
drivers/gpu/drm/Kconfig | 7 +------
drivers/gpu/drm/Makefile | 1 -
drivers/video/Kconfig | 4 ++++
drivers/video/Makefile | 1 +
.../drm/drm_nomodeset.c => video/nomodeset.c} | 12 +++++++-----
include/drm/drm_drv.h | 8 +++++++-
include/video/nomodeset.h | 8 ++++++++
9 files changed, 39 insertions(+), 19 deletions(-)
rename drivers/{gpu/drm/drm_nomodeset.c => video/nomodeset.c} (63%)
create mode 100644 include/video/nomodeset.h
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a465d5242774a..88561b3ce28a4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3777,12 +3777,15 @@
shutdown the other cpus. Instead use the REBOOT_VECTOR
irq.
- nomodeset Disable kernel modesetting. DRM drivers will not perform
- display-mode changes or accelerated rendering. Only the
- system framebuffer will be available for use if this was
- set-up by the firmware or boot loader.
-
- Useful as fallback, or for testing and debugging.
+ nomodeset Disable kernel modesetting. Most systems' firmware
+ sets up a display mode and provides framebuffer memory
+ for output. With nomodeset, DRM and fbdev drivers will
+ not load if they could possibly displace the pre-
+ initialized output. Only the system framebuffer will
+ be available for use. The respective drivers will not
+ perform display-mode changes or accelerated rendering.
+
+ Useful as error fallback, or for testing and debugging.
nomodule Disable module load
diff --git a/MAINTAINERS b/MAINTAINERS
index 0f624e3ef6235..84b008f5aacbc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6698,8 +6698,10 @@ F: drivers/gpu/drm/drm_aperture.c
F: drivers/gpu/drm/tiny/ofdrm.c
F: drivers/gpu/drm/tiny/simpledrm.c
F: drivers/video/aperture.c
+F: drivers/video/nomodeset.c
F: include/drm/drm_aperture.h
F: include/linux/aperture.h
+F: include/video/nomodeset.h
DRM DRIVER FOR SIS VIDEO CARDS
S: Orphan / Obsolete
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index f30f99166531f..6b11614aecc5b 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -8,7 +8,6 @@
menuconfig DRM
tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)"
depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && HAS_DMA
- select DRM_NOMODESET
select DRM_PANEL_ORIENTATION_QUIRKS
select HDMI
select FB_CMDLINE
@@ -19,6 +18,7 @@ menuconfig DRM
# gallium uses SYS_kcmp for os_same_file_description() to de-duplicate
# device and dmabuf fd. Let's make sure that is available for our userspace.
select KCMP
+ select VIDEO_NOMODESET
help
Kernel-level support for the Direct Rendering Infrastructure (DRI)
introduced in XFree86 4.0. If you say Y here, you need to select
@@ -515,11 +515,6 @@ config DRM_EXPORT_FOR_TESTS
config DRM_PANEL_ORIENTATION_QUIRKS
tristate
-# Separate option because nomodeset parameter is global and expected built-in
-config DRM_NOMODESET
- bool
- default n
-
config DRM_LIB_RANDOM
bool
default n
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index c44a54cadb618..f92cd78927110 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -72,7 +72,6 @@ drm-$(CONFIG_DRM_PRIVACY_SCREEN) += \
drm_privacy_screen_x86.o
obj-$(CONFIG_DRM) += drm.o
-obj-$(CONFIG_DRM_NOMODESET) += drm_nomodeset.o
obj-$(CONFIG_DRM_PANEL_ORIENTATION_QUIRKS) += drm_panel_orientation_quirks.o
#
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 0587e21abad94..6d2fde6c5d11a 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -11,6 +11,10 @@ config APERTURE_HELPERS
Support tracking and hand-over of aperture ownership. Required
by graphics drivers for firmware-provided framebuffers.
+config VIDEO_NOMODESET
+ bool
+ default n
+
if HAS_IOMEM
config HAVE_FB_ATMEL
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 5bb6b452cc83a..a50eb528ed3c3 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -2,6 +2,7 @@
obj-$(CONFIG_APERTURE_HELPERS) += aperture.o
obj-$(CONFIG_VGASTATE) += vgastate.o
+obj-$(CONFIG_VIDEO_NOMODESET) += nomodeset.o
obj-$(CONFIG_HDMI) += hdmi.o
obj-$(CONFIG_VT) += console/
diff --git a/drivers/gpu/drm/drm_nomodeset.c b/drivers/video/nomodeset.c
similarity index 63%
rename from drivers/gpu/drm/drm_nomodeset.c
rename to drivers/video/nomodeset.c
index f3978d5bd3a1d..13cc8b7196978 100644
--- a/drivers/gpu/drm/drm_nomodeset.c
+++ b/drivers/video/nomodeset.c
@@ -3,17 +3,19 @@
#include <linux/module.h>
#include <linux/types.h>
-static bool drm_nomodeset;
+#include <video/nomodeset.h>
-bool drm_firmware_drivers_only(void)
+static bool video_nomodeset;
+
+bool video_firmware_drivers_only(void)
{
- return drm_nomodeset;
+ return video_nomodeset;
}
-EXPORT_SYMBOL(drm_firmware_drivers_only);
+EXPORT_SYMBOL(video_firmware_drivers_only);
static int __init disable_modeset(char *str)
{
- drm_nomodeset = true;
+ video_nomodeset = true;
pr_warn("Booted with the nomodeset parameter. Only the system framebuffer will be available\n");
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index f6159acb88569..700d3857e0881 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -30,6 +30,8 @@
#include <linux/list.h>
#include <linux/irqreturn.h>
+#include <video/nomodeset.h>
+
#include <drm/drm_device.h>
struct drm_file;
@@ -602,6 +604,10 @@ static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
int drm_dev_set_unique(struct drm_device *dev, const char *name);
-extern bool drm_firmware_drivers_only(void);
+/* TODO: Inline drm_firmware_drivers_only() in all its callers. */
+static inline bool drm_firmware_drivers_only(void)
+{
+ return video_firmware_drivers_only();
+}
#endif
diff --git a/include/video/nomodeset.h b/include/video/nomodeset.h
new file mode 100644
index 0000000000000..8f8688b8beabe
--- /dev/null
+++ b/include/video/nomodeset.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: MIT */
+
+#ifndef VIDEO_NOMODESET_H
+#define VIDEO_NOMODESET_H
+
+bool video_firmware_drivers_only(void);
+
+#endif
--
2.38.0
