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Why are they needed? Please elaborate. > Fix this by doing the dc state copy right after the dc_commit_state() > call. > > Cc: Nicholas Kazlauskas > Cc: Harry Wentland > Reviewed-by: Rodrigo Siqueira > Signed-off-by: Aurabindo Pillai > --- > .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > index 63f076a46260..17a9108f8186 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > @@ -7999,15 +7999,8 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state) > drm_atomic_helper_update_legacy_modeset_state(dev, state); > > dm_state = dm_atomic_get_new_state(state); > - if (dm_state && dm_state->context) { > + if (dm_state && dm_state->context) > dc_state = dm_state->context; > - } else { > - /* No state changes, retain current state. */ > - dc_state_temp = dc_create_state(dm->dc); > - ASSERT(dc_state_temp); > - dc_state = dc_state_temp; > - dc_resource_state_copy_construct_current(dm->dc, dc_state); > - } If I understand this right this change means that when we do a "fast" update we'll simply modify the existing dc_state directly, instead of operating on a copy. Is this safe? Keep in mind that calls in amdgpu_dm can be multi-threaded, unlike calls on other OSes that use our driver. In particular, it looks like dm_enable_per_frame_crtc_master_sync is called on dc_state before the dc_lock is taken. Could this lead to issues similar to the ones outlined by Nick in his commit when he wrote this code: eb3dc8978596 ("drm/amd/display: Use private obj helpers for dm_atomic_state") > > for_each_oldnew_crtc_in_state (state, crtc, old_crtc_state, > new_crtc_state, i) { > @@ -8127,6 +8120,14 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state) > mutex_unlock(&dm->dc_lock); > } > > + if (dc_state == NULL) { > + /* No state changes, retain current state. */ > + dc_state_temp = dc_create_state(dm->dc); > + ASSERT(dc_state_temp); > + dc_state = dc_state_temp; > + dc_resource_state_copy_construct_current(dm->dc, dc_state); > + } > + Does moving this down serve a purpose other than the one to preserve this code? Moving this means that dc_commit_state (now delegating to dc_commit_streams on some ASICs) is operating on dc->current_state whereas dc_commit_updates_for_stream (now delegating to dc_update_planes_and_stream on some ASICs) is operating on the state copy, i.e. the local dc_state. Is this really the intention? Will this make our lives easier or harder? This code is already hard to parse. I fail to see how this will improve that situation. Harry > for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) { > struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc); >