From 86de88cfeb7cf33c7bbd18360e041c7d4e651bba Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Mon, 4 Nov 2019 09:37:36 -0800 Subject: drm/atomic: fix self-refresh helpers crtc state dereference drm_self_refresh_helper_update_avg_times() was incorrectly accessing the new incoming state after drm_atomic_helper_commit_hw_done(). But this state might have already been superceeded by an !nonblock atomic update resulting in dereferencing an already free'd crtc_state. TODO I *think* this will more or less do the right thing.. althought I'm not 100% sure if, for example, we enter psr in a nonblock commit, and then leave psr in a !nonblock commit that overtakes the completion of the nonblock commit. Not sure if this sort of scenario can happen in practice. But not crashing is better than crashing, so I guess we should either take this patch or rever the self-refresh helpers until Sean can figure out a better solution. Fixes: d4da4e33341c ("drm: Measure Self Refresh Entry/Exit times to avoid thrashing") Cc: Sean Paul Signed-off-by: Rob Clark [seanpaul fixed up some checkpatch warns] Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20191104173737.142558-1-robdclark@gmail.com --- drivers/gpu/drm/drm_atomic_helper.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/drm_atomic_helper.c') diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 3ef2ac52ce94..2dd2cd87cdbb 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1581,8 +1581,11 @@ static void commit_tail(struct drm_atomic_state *old_state) { struct drm_device *dev = old_state->dev; const struct drm_mode_config_helper_funcs *funcs; + struct drm_crtc_state *new_crtc_state; + struct drm_crtc *crtc; ktime_t start; s64 commit_time_ms; + unsigned int i, new_self_refresh_mask = 0; funcs = dev->mode_config.helper_private; @@ -1602,6 +1605,15 @@ static void commit_tail(struct drm_atomic_state *old_state) drm_atomic_helper_wait_for_dependencies(old_state); + /* + * We cannot safely access new_crtc_state after + * drm_atomic_helper_commit_hw_done() so figure out which crtc's have + * self-refresh active beforehand: + */ + for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i) + if (new_crtc_state->self_refresh_active) + new_self_refresh_mask |= BIT(i); + if (funcs && funcs->atomic_commit_tail) funcs->atomic_commit_tail(old_state); else @@ -1610,7 +1622,8 @@ static void commit_tail(struct drm_atomic_state *old_state) commit_time_ms = ktime_ms_delta(ktime_get(), start); if (commit_time_ms > 0) drm_self_refresh_helper_update_avg_times(old_state, - (unsigned long)commit_time_ms); + (unsigned long)commit_time_ms, + new_self_refresh_mask); drm_atomic_helper_commit_cleanup_done(old_state); -- cgit v1.2.3