drm/fbdev: Return -EBUSY when oopsing
Trying to do anything with kms drivers when oopsing has become a
failing proposition. But since we can end up in the fbdev code simply
due to the console unblanking that's done unconditionally just
removing our panic handler isn't enough. We need to block all fbdev
callbacks when oopsing.
There was already one in the blank handler, but it failed silently.
That makes it impossible for drivers (like i915) who subclass these
functions to figure this out.
Instead consistently return -EBUSY so that everyone knows that we
really don't want to be bothered right now. This also allows us to
remove a pile of FIXMEs from the i915 fbdev code (since due to the
failure code they now won't attempt to grab dangerous locks any more).
Cc: Dave Airlie <airlied@gmail.com>
Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index c1cb753..f16eed0 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -491,14 +491,6 @@
int i, j;
/*
- * fbdev->blank can be called from irq context in case of a panic.
- * Since we already have our own special panic handler which will
- * restore the fbdev console mode completely, just bail out early.
- */
- if (oops_in_progress)
- return;
-
- /*
* For each CRTC in this fb, turn the connectors on/off.
*/
drm_modeset_lock_all(dev);
@@ -531,6 +523,9 @@
*/
int drm_fb_helper_blank(int blank, struct fb_info *info)
{
+ if (oops_in_progress)
+ return -EBUSY;
+
switch (blank) {
/* Display: On; HSync: On, VSync: On */
case FB_BLANK_UNBLANK:
@@ -978,9 +973,10 @@
int i, j, rc = 0;
int start;
- if (__drm_modeset_lock_all(dev, !!oops_in_progress)) {
+ if (oops_in_progress)
return -EBUSY;
- }
+
+ drm_modeset_lock_all(dev);
if (!drm_fb_helper_is_bound(fb_helper)) {
drm_modeset_unlock_all(dev);
return -EBUSY;
@@ -1129,6 +1125,9 @@
struct drm_fb_helper *fb_helper = info->par;
struct fb_var_screeninfo *var = &info->var;
+ if (oops_in_progress)
+ return -EBUSY;
+
if (var->pixclock != 0) {
DRM_ERROR("PIXEL CLOCK SET\n");
return -EINVAL;
@@ -1154,9 +1153,10 @@
int ret = 0;
int i;
- if (__drm_modeset_lock_all(dev, !!oops_in_progress)) {
+ if (oops_in_progress)
return -EBUSY;
- }
+
+ drm_modeset_lock_all(dev);
if (!drm_fb_helper_is_bound(fb_helper)) {
drm_modeset_unlock_all(dev);
return -EBUSY;