[PATCH 3/4] drm/fb-helper: Add module option to disable fbdev emulation

Daniel Vetter
2015-08-25T13:45:24Z

Faster than recompiling.

Note that restore_fbdev_mode_unlocked is a bit special and the only
one which returns an error code when fbdev isn't there - i915 needs
that one to not fall over with some additional fbcon related restore
code. Everyone else just ignores the return value or only prints a
DRM_DEBUG level message.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/drm_fb_helper.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 83aacb0cc9df..8259dec1de1f 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -39,6 +39,11 @@
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>

+static bool drm_fbdev_emulation = true;
+module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600);
+MODULE_PARM_DESC(fbdev_emulation,
+ "Enable legacy fbdev emulation [default=true]");
+
static LIST_HEAD(kernel_fb_helper_list);

/**
@@ -99,6 +104,9 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
struct drm_connector *connector;
int i;

+ if (!drm_fbdev_emulation)
+ return 0;
+
mutex_lock(&dev->mode_config.mutex);
drm_for_each_connector(connector, dev) {
struct drm_fb_helper_connector *fb_helper_connector;
@@ -129,6 +137,9 @@ int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct drm_
struct drm_fb_helper_connector **temp;
struct drm_fb_helper_connector *fb_helper_connector;

+ if (!drm_fbdev_emulation)
+ return 0;
+
WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));
if (fb_helper->connector_count + 1 > fb_helper->connector_info_alloc_count) {
temp = krealloc(fb_helper->connector_info, sizeof(struct drm_fb_helper_connector *) * (fb_helper->connector_count + 1), GFP_KERNEL);
@@ -184,6 +195,9 @@ int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
struct drm_fb_helper_connector *fb_helper_connector;
int i, j;

+ if (!drm_fbdev_emulation)
+ return 0;
+
WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));

for (i = 0; i < fb_helper->connector_count; i++) {
@@ -375,6 +389,9 @@ int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
bool do_delayed
int ret;

+ if (!drm_fbdev_emulation)
+ return -ENODEV;
+
drm_modeset_lock_all(dev);
ret = restore_fbdev_mode(fb_helper);

@@ -591,6 +608,9 @@ int drm_fb_helper_init(struct drm_device *dev,
struct drm_crtc *crtc;
int i;

+ if (!drm_fbdev_emulation)
+ return 0;
+
if (!max_conn_count)
return -EINVAL;

@@ -713,6 +733,9 @@ EXPORT_SYMBOL(drm_fb_helper_release_fbi);

void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
{
+ if (!drm_fbdev_emulation)
+ return;
+
if (!list_empty(&fb_helper->kernel_fb_list)) {
list_del(&fb_helper->kernel_fb_list);
if (list_empty(&kernel_fb_helper_list)) {
@@ -1933,6 +1956,9 @@ int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
struct drm_device *dev = fb_helper->dev;
int count = 0;

+ if (!drm_fbdev_emulation)
+ return 0;
+
mutex_lock(&dev->mode_config.mutex);
count = drm_fb_helper_probe_connector_modes(fb_helper,
dev->mode_config.max_width,
@@ -1976,6 +2002,9 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
struct drm_device *dev = fb_helper->dev;
u32 max_width, max_height;

+ if (!drm_fbdev_emulation)
+ return 0;
+
mutex_lock(&fb_helper->dev->mode_config.mutex);
if (!fb_helper->fb || !drm_fb_helper_is_bound(fb_helper)) {
fb_helper->delayed_hotplug = true;
--
1.8.3.1