fbdev: Drop FBINFO_CAN_FORCE_OUTPUT flag

This was only added for the drm's fbdev emulation support, so that it
would try harder to show the Oops.

Unfortunately this never really worked reliably, and in practice ended
up pushing the real Oops off the screen due to plentyfull locking,
sleep-while-atomic and other issues. So we removed all that support
from the fbdev emulation a while back. Aside: We've also removed the
kgdb support, for similar reasons.

Since it's such a small patch I figured I don't split this up into the
usual 3-phase removal.
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Alexander Kapshuk <alexander.kapshuk@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: David Lechner <david@lechnology.com>
Cc: nouveau@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180822085405.10787-1-daniel.vetter@ffwll.ch

drivers/gpu/drm/nouveau/nouveau_fbcon.c

@@ -379,7 +379,6 @@ nouveau_fbcon_create(struct drm_fb_helper *helper,
 		info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_COPYAREA |
 			      FBINFO_HWACCEL_FILLRECT |
 			      FBINFO_HWACCEL_IMAGEBLIT;
-	info->flags |= FBINFO_CAN_FORCE_OUTPUT;
 	info->fbops = &nouveau_fbcon_sw_ops;
 	info->fix.smem_start = fb->nvbo->bo.mem.bus.base +
 			       fb->nvbo->bo.mem.bus.offset;

drivers/staging/vboxvideo/vbox_fb.c

@@ -155,8 +155,7 @@ static int vboxfb_create(struct drm_fb_helper *helper,
 	 * The last flag forces a mode set on VT switches even if the kernel
 	 * does not think it is needed.
 	 */
-	info->flags = FBINFO_DEFAULT | FBINFO_CAN_FORCE_OUTPUT |
-		      FBINFO_MISC_ALWAYS_SETPAR;
+	info->flags = FBINFO_DEFAULT | FBINFO_MISC_ALWAYS_SETPAR;
 	info->fbops = &vboxfb_ops;
 
 	/*

drivers/video/fbdev/core/fbcon.c

@@ -1104,7 +1104,6 @@ static void fbcon_init(struct vc_data *vc, int init)
 	if (p->userfont)
 		charcnt = FNTCHARCNT(p->fontdata);
 
-	vc->vc_panic_force_write = !!(info->flags & FBINFO_CAN_FORCE_OUTPUT);
 	vc->vc_can_do_color = (fb_get_color_depth(&info->var, &info->fix)!=1);
 	vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
 	if (charcnt == 256) {

include/linux/fb.h

@@ -457,10 +457,6 @@ struct fb_tile_ops {
  */
 #define FBINFO_BE_MATH  0x100000
 
-/* report to the VT layer that this fb driver can accept forced console
-   output like oopses */
-#define FBINFO_CAN_FORCE_OUTPUT     0x200000
-
 struct fb_info {
 	atomic_t count;
 	int node;