From 832d5bfd67f9b723b7b5662b8c187b43aa5d2ac8 Mon Sep 17 00:00:00 2001 From: Mika Kahola Date: Tue, 2 Feb 2016 15:16:40 +0200 Subject: [PATCH] drm/i915: DisplayPort-MST pixel clock check MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 DisplayPort MST. V2: - removed computation for max pixel clock V3: - cleanup by removing unnecessary lines V4: - max_pixclk variable renamed as max_dotclk Signed-off-by: Mika Kahola Reviewed-by: Ville Syrjälä Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1454419003-6001-4-git-send-email-mika.kahola@intel.com --- drivers/gpu/drm/i915/intel_dp_mst.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index 2a2ab306ad84..a2bd698fe2f7 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -371,6 +371,8 @@ static enum drm_mode_status intel_dp_mst_mode_valid(struct drm_connector *connector, struct drm_display_mode *mode) { + int max_dotclk = to_i915(connector->dev)->max_dotclk_freq; + /* TODO - validate mode against available PBN for link */ if (mode->clock < 10000) return MODE_CLOCK_LOW; @@ -378,6 +380,9 @@ intel_dp_mst_mode_valid(struct drm_connector *connector, if (mode->flags & DRM_MODE_FLAG_DBLCLK) return MODE_H_ILLEGAL; + if (mode->clock > max_dotclk) + return MODE_CLOCK_HIGH; + return MODE_OK; } -- 2.20.1