[Intel-gfx] [PATCH 6/9] drm/i915: Check pixel clock when setting mode for DSI

[Mika Kahola]

It is possible the we request to have a mode that has
higher pixel clock than our HW can support. This patch
checks if requested pixel clock is lower than the one
supported by the HW. The requested mode is discarded
if we cannot support the requested pixel clock.

This patch applies to DSI.

Signed-off-by: Mika Kahola <mika.kahola at intel.com>
---
 drivers/gpu/drm/i915/intel_dsi.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 98998e9..1cf35b8 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -635,15 +635,39 @@ static void intel_dsi_get_config(struct intel_encoder *encoder,
 	pipe_config->port_clock = pclk;
 }
 
+static int
+intel_dsi_max_pixclk(struct intel_dsi *intel_dsi)
+{
+	struct drm_device *dev = intel_dsi->base.base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct intel_crtc *intel_crtc = to_intel_crtc(intel_dsi->base.base.crtc);
+
+	if (IS_CHERRYVIEW(dev))
+		return  DIV_ROUND_UP(dev_priv->max_cdclk_freq * 100, 95);
+	else if (IS_VALLEYVIEW(dev))
+		return  DIV_ROUND_UP(dev_priv->max_cdclk_freq * 100, 90);
+	else if (IS_BROADWELL(dev) && intel_crtc->config->ips_enabled)
+		return  DIV_ROUND_UP(dev_priv->max_cdclk_freq * 100, 95);
+	else
+		return dev_priv->max_cdclk_freq;
+}
+
 static enum drm_mode_status
 intel_dsi_mode_valid(struct drm_connector *connector,
 		     struct drm_display_mode *mode)
 {
 	struct intel_connector *intel_connector = to_intel_connector(connector);
 	struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;
+	struct intel_encoder *intel_encoder = intel_connector->encoder;
+	struct drm_encoder *encoder = &intel_encoder->base;
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
+	int max_pixclk = intel_dsi_max_pixclk(intel_dsi);
 
 	DRM_DEBUG_KMS("\n");
 
+	if (mode->clock > max_pixclk)
+		return MODE_PANEL;
+
 	if (mode->flags & DRM_MODE_FLAG_DBLSCAN) {
 		DRM_DEBUG_KMS("MODE_NO_DBLESCAN\n");
 		return MODE_NO_DBLESCAN;
-- 
1.9.1