drm/client: Pass force parameter to client restore

Add force parameter to client restore and pass value through the
layers. The only currently used value is false.

If force is true, the client should restore its display even if it
does not hold the DRM master lock. This is be required for emergency
output, such as sysrq.

While at it, inline drm_fb_helper_lastclose(), which is a trivial
wrapper around drm_fb_helper_restore_fbdev_mode_unlocked().

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20251110154616.539328-2-tzimmermann@suse.de

1 files changed, 6 insertions, 18 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 53e9dc0543de..1392738ce2fe 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -255,6 +255,7 @@ __drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
 /**
  * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
  * @fb_helper: driver-allocated fbdev helper, can be NULL
+ * @force: ignore present DRM master
  *
  * This helper should be called from fbdev emulation's &drm_client_funcs.restore
  * callback. It ensures that the user isn't greeted with a black screen when the
@@ -263,9 +264,9 @@ __drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
  * Returns:
  * 0 on success, or a negative errno code otherwise.
  */
-int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
+int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper, bool force)
 {
-	return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, false);
+	return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
 }
 EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
 
@@ -1328,9 +1329,9 @@ int drm_fb_helper_set_par(struct fb_info *info)
 	 * 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.
+	 * In the past this was caught by drm_fb_helper_restore_fbdev_mode_unlocked(),
+	 * 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
@@ -1955,16 +1956,3 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
 	return 0;
 }
 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
-
-/**
- * drm_fb_helper_lastclose - DRM driver lastclose helper for fbdev emulation
- * @dev: DRM device
- *
- * This function is obsolete. Call drm_fb_helper_restore_fbdev_mode_unlocked()
- * instead.
- */
-void drm_fb_helper_lastclose(struct drm_device *dev)
-{
-	drm_fb_helper_restore_fbdev_mode_unlocked(dev->fb_helper);
-}
-EXPORT_SYMBOL(drm_fb_helper_lastclose);