drm/i915: Tolerate bogus DPLL selection

Let's check that we actually found the PLL before doing the port_clock readout, just in case the hardware was severly misprogrammed by the previous guy. Not sure the hw would even survive such misprogramming without hanging but no real harm in checking anyway. Cc: Karthik B S <[email protected]> Signed-off-by: Ville Syrjälä <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] Reviewed-by: Karthik B S <[email protected]>
sm00th · Mar 11, 2021 · 086877a · 086877a
1 parent 35bb28e
commit 086877a
Showing 1 changed file with 13 additions and 4 deletions.
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3716,6 +3716,9 @@ void intel_ddi_get_clock(struct intel_encoder *encoder,
 	struct icl_port_dpll *port_dpll = &crtc_state->icl_port_dplls[port_dpll_id];
 	bool pll_active;
 
+	if (drm_WARN_ON(&i915->drm, !pll))
+		return;
+
 	port_dpll->pll = pll;
 	pll_active = intel_dpll_get_hw_state(i915, pll, &port_dpll->hw_state);
 	drm_WARN_ON(&i915->drm, !pll_active);
@@ -3754,16 +3757,17 @@ static void icl_ddi_combo_get_config(struct intel_encoder *encoder,
 	intel_ddi_get_config(encoder, crtc_state);
 }
 
-static void icl_ddi_tc_get_config(struct intel_encoder *encoder,
-				  struct intel_crtc_state *crtc_state)
+static void icl_ddi_tc_get_clock(struct intel_encoder *encoder,
+				 struct intel_crtc_state *crtc_state,
+				 struct intel_shared_dpll *pll)
 {
 	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
 	enum icl_port_dpll_id port_dpll_id;
 	struct icl_port_dpll *port_dpll;
-	struct intel_shared_dpll *pll;
 	bool pll_active;
 
-	pll = icl_ddi_tc_get_pll(encoder);
+	if (drm_WARN_ON(&i915->drm, !pll))
+		return;
 
 	if (intel_get_shared_dpll_id(i915, pll) == DPLL_ID_ICL_TBTPLL)
 		port_dpll_id = ICL_PORT_DPLL_DEFAULT;
@@ -3783,7 +3787,12 @@ static void icl_ddi_tc_get_config(struct intel_encoder *encoder,
 	else
 		crtc_state->port_clock = intel_dpll_get_freq(i915, crtc_state->shared_dpll,
 							     &crtc_state->dpll_hw_state);
+}
 
+static void icl_ddi_tc_get_config(struct intel_encoder *encoder,
+				  struct intel_crtc_state *crtc_state)
+{
+	icl_ddi_tc_get_clock(encoder, crtc_state, icl_ddi_tc_get_pll(encoder));
 	intel_ddi_get_config(encoder, crtc_state);
 }