Created attachment 129186 [details] stack trace Steps to reproduce: - Connect a 4K DP MST monitor to the USB-C port on a BXT system using a USB-C to DP dongle while the system is up - Or boot a BXT system with a 4K DP MST monitor attached to the USB-C port using a USB-C to DP dongle Result: - The system hangs or reboots immediately. Notes: Tentative fix: https://lists.freedesktop.org/archives/intel-gfx/2017-January/116654.html Adds the missing INTEL_OUTPUT_DP_MST case in bxt_get_dpll() to correctly initialize the crtc_state and port plls when link training a DP MST monitor on BXT/APL devices.
Created attachment 129187 [details] attachment-9910-0.html Dear sender, OOO from ww4.5 to ww5.4 for chinese new year. Email response will be slow/delay. Sorry for the inconvenience. Best regards, Shawn
I added the following check to make sure I trigger a stack trace otherwise the system would reboot without giving me the crash log: @@ -1862,6 +1863,10 @@ bool bxt_ddi_dp_set_dpll_hw_state(int clock, memset(&crtc_state->dpll_hw_state, 0, sizeof(crtc_state->dpll_hw_state)); + if (!memcmp(&zeroes, &dpll_hw_state, + sizeof(crtc_state->dpll_hw_state))) + BUG(); + crtc_state->dpll_hw_state = dpll_hw_state; if (encoder->type == INTEL_OUTPUT_DP_MST) {
Reference to Shawn Lee's patch: https://patchwork.freedesktop.org/series/17815/
Presumed fixed by commit 0aab2c721d81590012a5021a516f00666646741f Author: Lee, Shawn C <shawn.c.lee@intel.com> Date: Fri Feb 3 12:32:09 2017 +0800 drm/i915/bxt: Add MST support when do DPLL calculation Please reopen if the problem persists with that.
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