[34-longterm 107/260] drm: Only decouple the old_fb from the crtc is we call mode_set*

Paul Gortmaker
2011-01-02T07:23:30Z

From: Chris Wilson <chris@chris-wilson.co.uk>

commit 356ad3cd616185631235ffb48b3efbf39f9923b3 upstream.

Otherwise when disabling the output we switch to the new fb (which is
likely NULL) and skip the call to mode_set -- leaking driver private
state on the old_fb.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29857
Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/gpu/drm/drm_crtc_helper.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 51103aa..220177a 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -921,13 +921,13 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
mode_changed = true;

if (mode_changed) {
- old_fb = set->crtc->fb;
- set->crtc->fb = set->fb;
set->crtc->enabled = (set->mode != NULL);
if (set->mode != NULL) {
DRM_DEBUG_KMS("attempting to set mode from"
" userspace\n");
drm_mode_debug_printmodeline(set->mode);
+ old_fb = set->crtc->fb;
+ set->crtc->fb = set->fb;
if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
set->x, set->y,
old_fb)) {
--
1.7.3.3