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path: root/drivers/firmware/sysfb.c
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Diffstat (limited to 'drivers/firmware/sysfb.c')
-rw-r--r--drivers/firmware/sysfb.c58
1 files changed, 50 insertions, 8 deletions
diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c
index 2bfbb05f7d89..1f276f108cc9 100644
--- a/drivers/firmware/sysfb.c
+++ b/drivers/firmware/sysfb.c
@@ -34,21 +34,59 @@
#include <linux/screen_info.h>
#include <linux/sysfb.h>
+static struct platform_device *pd;
+static DEFINE_MUTEX(disable_lock);
+static bool disabled;
+
+static bool sysfb_unregister(void)
+{
+ if (IS_ERR_OR_NULL(pd))
+ return false;
+
+ platform_device_unregister(pd);
+ pd = NULL;
+
+ return true;
+}
+
+/**
+ * sysfb_disable() - disable the Generic System Framebuffers support
+ *
+ * This disables the registration of system framebuffer devices that match the
+ * generic drivers that make use of the system framebuffer set up by firmware.
+ *
+ * It also unregisters a device if this was already registered by sysfb_init().
+ *
+ * Context: The function can sleep. A @disable_lock mutex is acquired to serialize
+ * against sysfb_init(), that registers a system framebuffer device.
+ */
+void sysfb_disable(void)
+{
+ mutex_lock(&disable_lock);
+ sysfb_unregister();
+ disabled = true;
+ mutex_unlock(&disable_lock);
+}
+EXPORT_SYMBOL_GPL(sysfb_disable);
+
static __init int sysfb_init(void)
{
struct screen_info *si = &screen_info;
struct simplefb_platform_data mode;
- struct platform_device *pd;
const char *name;
bool compatible;
- int ret;
+ int ret = 0;
+
+ mutex_lock(&disable_lock);
+ if (disabled)
+ goto unlock_mutex;
/* try to create a simple-framebuffer device */
compatible = sysfb_parse_mode(si, &mode);
if (compatible) {
- ret = sysfb_create_simplefb(si, &mode);
- if (!ret)
- return 0;
+ pd = sysfb_create_simplefb(si, &mode);
+ if (!IS_ERR(pd))
+ goto unlock_mutex;
}
/* if the FB is incompatible, create a legacy framebuffer device */
@@ -60,8 +98,10 @@ static __init int sysfb_init(void)
name = "platform-framebuffer";
pd = platform_device_alloc(name, 0);
- if (!pd)
- return -ENOMEM;
+ if (!pd) {
+ ret = -ENOMEM;
+ goto unlock_mutex;
+ }
sysfb_apply_efi_quirks(pd);
@@ -73,9 +113,11 @@ static __init int sysfb_init(void)
if (ret)
goto err;
- return 0;
+ goto unlock_mutex;
err:
platform_device_put(pd);
+unlock_mutex:
+ mutex_unlock(&disable_lock);
return ret;
}