}
EXPORT_SYMBOL(drm_fb_helper_debug_leave);
-/**
- * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
- * @fb_helper: driver-allocated fbdev helper, can be NULL
- *
- * This should be called from driver's drm &drm_driver.lastclose callback
- * when implementing an fbcon on top of kms using this helper. This ensures that
- * the user isn't greeted with a black screen when e.g. X dies.
- *
- * RETURNS:
- * Zero if everything went ok, negative error code otherwise.
- */
-int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
+static int
+__drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
+ bool force)
{
bool do_delayed;
int ret;
return 0;
mutex_lock(&fb_helper->lock);
- ret = drm_client_modeset_commit(&fb_helper->client);
+ if (force) {
+ /*
+ * Yes this is the _locked version which expects the master lock
+ * to be held. But for forced restores we're intentionally
+ * racing here, see drm_fb_helper_set_par().
+ */
+ ret = drm_client_modeset_commit_locked(&fb_helper->client);
+ } else {
+ ret = drm_client_modeset_commit(&fb_helper->client);
+ }
do_delayed = fb_helper->delayed_hotplug;
if (do_delayed)
return ret;
}
+
+/**
+ * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
+ * @fb_helper: driver-allocated fbdev helper, can be NULL
+ *
+ * This should be called from driver's drm &drm_driver.lastclose callback
+ * when implementing an fbcon on top of kms using this helper. This ensures that
+ * the user isn't greeted with a black screen when e.g. X dies.
+ *
+ * RETURNS:
+ * Zero if everything went ok, negative error code otherwise.
+ */
+int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
+{
+ return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, false);
+}
EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
#ifdef CONFIG_MAGIC_SYSRQ
{
struct drm_fb_helper *fb_helper = info->par;
struct fb_var_screeninfo *var = &info->var;
+ bool force;
if (oops_in_progress)
return -EBUSY;
return -EINVAL;
}
- drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
+ /*
+ * Normally we want to make sure that a kms master takes precedence over
+ * fbdev, to avoid fbdev flickering and occasionally stealing the
+ * display status. But Xorg first sets the vt back to text mode using
+ * the KDSET IOCTL with KD_TEXT, and only after that drops the master
+ * status when exiting.
+ *
+ * In the past this was caught by drm_fb_helper_lastclose(), but on
+ * modern systems where logind always keeps a drm fd open to orchestrate
+ * the vt switching, this doesn't work.
+ *
+ * To not break the userspace ABI we have this special case here, which
+ * is only used for the above case. Everything else uses the normal
+ * commit function, which ensures that we never steal the display from
+ * an active drm master.
+ */
+ force = var->activate & FB_ACTIVATE_KD_TEXT;
+
+ __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
return 0;
}