mirror of https://gitee.com/openkylin/linux.git
45ef40aab7
The short pulse handler checks if channel equalization is okay and goes onto retrain a link if there are active MST links. This retraining path is not meant for new MST connections, but due to a bug elsewhere, if active_mst_links is < 0 the boolean check for active_mst_links passes and we proceed to retrain a new link. This results in a sequence of failed link training attempts, most likely due to the hardware not setup for link training at that point i.e., missing the DDI pre_enable sequence. [ 80.301272] [drm:intel_dp_check_mst_status] channel EQ not ok, retraining [ 80.301312] [drm:intel_ddi_prepare_link_retrain] *ERROR* Timeout waiting for DDI BUF C idle bit The above error gives us a hint something went wrong before link training started. Check for a positive value of active_mst_links and throw in a warning for invalid active_mst_links as debug aid. Cc: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com> Tested-by: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180718171943.3246-1-dhinakaran.pandiyan@intel.com |
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