drm/i915: Update comment in clear_intel_crtc_state()

Explain why a few fields of the new pipe_config have their values
preserved, while the others are zeroed.

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 9d2d6fbbf3e3ba5925c3a80b963f5964d1a6c05f..4a34709794f0f26daf52617da679ce3da77cdd87 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11485,7 +11485,11 @@ clear_intel_crtc_state(struct intel_crtc_state *crtc_state)
        enum intel_dpll_id shared_dpll;
        uint32_t ddi_pll_sel;
 
-       /* Clear only the intel specific part of the crtc state excluding scalers */
+       /* FIXME: before the switch to atomic started, a new pipe_config was
+        * kzalloc'd. Code that depends on any field being zero should be
+        * fixed, so that the crtc_state can be safely duplicated. For now,
+        * only fields that are know to not cause problems are preserved. */
+
        tmp_state = crtc_state->base;
        scaler_state = crtc_state->scaler_state;
        shared_dpll = crtc_state->shared_dpll;