vt/console: try harder to print output when panicing
Jesse's initial patch commit said:
"At panic time (i.e. when oops_in_progress is set) we should try a bit
harder to update the screen and make sure output gets to the VT, since
some drivers are capable of flipping back to it.
So make sure we try to unblank and update the display if called from a
panic context."
I've enhanced this to add a flag to the vc that console layer can set to
indicate they want this behaviour to occur. This also adds support to
fbcon for that flag and adds an fb flag for drivers to indicate they want
to use the support. It enables this for KMS drivers.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: James Simmons <jsimmons@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 34bfb05..82f64ac 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -705,7 +705,10 @@
update_attr(vc);
clear_buffer_attributes(vc);
}
- if (update && vc->vc_mode != KD_GRAPHICS)
+
+ /* Forcibly update if we're panicing */
+ if ((update && vc->vc_mode != KD_GRAPHICS) ||
+ vt_force_oops_output(vc))
do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
}
set_cursor(vc);
@@ -743,6 +746,7 @@
vc->vc_hi_font_mask = 0;
vc->vc_complement_mask = 0;
vc->vc_can_do_color = 0;
+ vc->vc_panic_force_write = false;
vc->vc_sw->con_init(vc, init);
if (!vc->vc_complement_mask)
vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
@@ -2506,7 +2510,7 @@
goto quit;
}
- if (vc->vc_mode != KD_TEXT)
+ if (vc->vc_mode != KD_TEXT && !vt_force_oops_output(vc))
goto quit;
/* undraw cursor first */
@@ -3784,7 +3788,8 @@
return;
}
vc = vc_cons[fg_console].d;
- if (vc->vc_mode != KD_TEXT)
+ /* Try to unblank in oops case too */
+ if (vc->vc_mode != KD_TEXT && !vt_force_oops_output(vc))
return; /* but leave console_blanked != 0 */
if (blankinterval) {
@@ -3793,7 +3798,7 @@
}
console_blanked = 0;
- if (vc->vc_sw->con_blank(vc, 0, leaving_gfx))
+ if (vc->vc_sw->con_blank(vc, 0, leaving_gfx) || vt_force_oops_output(vc))
/* Low-level driver cannot restore -> do it ourselves */
update_screen(vc);
if (console_blank_hook)
diff --git a/drivers/gpu/drm/i915/intel_fb.c b/drivers/gpu/drm/i915/intel_fb.c
index 54acd8b..a79525f 100644
--- a/drivers/gpu/drm/i915/intel_fb.c
+++ b/drivers/gpu/drm/i915/intel_fb.c
@@ -130,7 +130,7 @@
strcpy(info->fix.id, "inteldrmfb");
- info->flags = FBINFO_DEFAULT;
+ info->flags = FBINFO_DEFAULT | FBINFO_CAN_FORCE_OUTPUT;
info->fbops = &intelfb_ops;
/* setup aperture base/size for vesafb takeover */
@@ -148,8 +148,6 @@
info->fix.smem_start = dev->mode_config.fb_base + obj_priv->gtt_offset;
info->fix.smem_len = size;
- info->flags = FBINFO_DEFAULT;
-
info->screen_base = ioremap_wc(dev->agp->base + obj_priv->gtt_offset,
size);
if (!info->screen_base) {
diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index 2fb2444..099f637 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -250,6 +250,7 @@
info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_COPYAREA |
FBINFO_HWACCEL_FILLRECT |
FBINFO_HWACCEL_IMAGEBLIT;
+ info->flags |= FBINFO_CAN_FORCE_OUTPUT;
info->fbops = &nouveau_fbcon_ops;
info->fix.smem_start = dev->mode_config.fb_base + nvbo->bo.offset -
dev_priv->vm_vram_base;
diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
index dc1634b..dbf8696 100644
--- a/drivers/gpu/drm/radeon/radeon_fb.c
+++ b/drivers/gpu/drm/radeon/radeon_fb.c
@@ -224,7 +224,7 @@
drm_fb_helper_fill_fix(info, fb->pitch, fb->depth);
- info->flags = FBINFO_DEFAULT;
+ info->flags = FBINFO_DEFAULT | FBINFO_CAN_FORCE_OUTPUT;
info->fbops = &radeonfb_ops;
tmp = radeon_bo_gpu_offset(rbo) - rdev->mc.vram_start;
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 3b3f574..26bf7cb 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -283,7 +283,8 @@
struct fbcon_ops *ops = info->fbcon_par;
return (info->state != FBINFO_STATE_RUNNING ||
- vc->vc_mode != KD_TEXT || ops->graphics);
+ vc->vc_mode != KD_TEXT || ops->graphics) &&
+ !vt_force_oops_output(vc);
}
static inline int get_color(struct vc_data *vc, struct fb_info *info,
@@ -1073,6 +1074,7 @@
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) {
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index 38fe59d..d7d9acd 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -105,6 +105,7 @@
struct vc_data **vc_display_fg; /* [!] Ptr to var holding fg console for this display */
unsigned long vc_uni_pagedir;
unsigned long *vc_uni_pagedir_loc; /* [!] Location of uni_pagedir variable for this console */
+ bool vc_panic_force_write; /* when oops/panic this VC can accept forced output/blanking */
/* additional information is in vt_kern.h */
};
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 0c5659c..f0268de 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -825,6 +825,10 @@
*/
#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 {
int node;
int flags;
diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h
index 7f56db4..56cce34 100644
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -100,6 +100,13 @@
int deflt);
int vty_init(const struct file_operations *console_fops);
+static inline bool vt_force_oops_output(struct vc_data *vc)
+{
+ if (oops_in_progress && vc->vc_panic_force_write)
+ return true;
+ return false;
+}
+
/*
* vc_screen.c shares this temporary buffer with the console write code so that
* we can easily avoid touching user space while holding the console spinlock.