Updating legacy gamma tables, e.g., via RandR doesn't work at all as of Linux 4.7-rc6.
Reason seems to be that the required call to drm_atomic_helper_commit_planes_on_crtc is skipped in intel_atomic_commit after userspace set new gamma tables, because neither crtc->state->planes_changed nor update_pipe (= pipe_config->update_pipe) are true.
Removing the check for planes_changed || update_pipe fixes gamma table updates.
The code for Linux 4.8 drm-next has changed a lot in that area wrt. 4.7, but the new code for 4.8 also removed those checks and calls drm_atomic_helper_commit_planes_on_crtc unconditionally, and legacy gamma lut updates work on drm-next, so this seems to be the right solution.
Tested also shutdown/reboot, suspend/resume, (un-)plugging displays, mode switches for resolution/refresh rate, display rotation, and page-flipping/pageflip timing on Intel HD Ironlake to confirm the fix apparently doesn't break anything under X11.
Signed-off-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Lionel Landwerlin lionel.g.landwerlin@intel.com Cc: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/intel_display.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 04452cf..eb8fb36 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -13685,7 +13685,6 @@ static int intel_atomic_commit(struct drm_device *dev, bool modeset = needs_modeset(crtc->state); struct intel_crtc_state *pipe_config = to_intel_crtc_state(crtc->state); - bool update_pipe = !modeset && pipe_config->update_pipe;
if (modeset && crtc->state->active) { update_scanline_offset(to_intel_crtc(crtc)); @@ -13699,8 +13698,7 @@ static int intel_atomic_commit(struct drm_device *dev, drm_atomic_get_existing_plane_state(state, crtc->primary)) intel_fbc_enable(intel_crtc);
- if (crtc->state->active && - (crtc->state->planes_changed || update_pipe)) + if (crtc->state->active) drm_atomic_helper_commit_planes_on_crtc(old_crtc_state);
if (pipe_config->base.active && needs_vblank_wait(pipe_config))