On Tue, 02 Feb 2016, Lyude cpaul@redhat.com wrote:
We don't actually check for INTEL_OUTPUT_DP_MST at all in here, as a result we skip assigning a DPLL to any DP MST ports, which makes link training fail, after which things just keep going downhill from there.
Apparently broken since
commit 82d35437018950c25200051733fb2fbf63cca86c Author: Satheeshakrishna M satheeshakrishna.m@intel.com Date: Thu Nov 13 14:55:20 2014 +0000
drm/i915/skl: Implementation of SKL DPLL programming
Consequently, this fixes DisplayPort MST causing kernel panics, machine check errors, etc. on Skylake.
Please copy-paste some traces for the commit message so it'll be easier to match bug reports and fixes later on.
BR, Jani.
Signed-off-by: Lyude cpaul@redhat.com
drivers/gpu/drm/i915/intel_ddi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index e6408e5..54a165b 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -1589,7 +1589,8 @@ skl_ddi_pll_select(struct intel_crtc *intel_crtc, DPLL_CFGCR2_KDIV(wrpll_params.kdiv) | DPLL_CFGCR2_PDIV(wrpll_params.pdiv) | wrpll_params.central_freq;
- } else if (intel_encoder->type == INTEL_OUTPUT_DISPLAYPORT) {
- } else if (intel_encoder->type == INTEL_OUTPUT_DISPLAYPORT ||
intel_encoder->type == INTEL_OUTPUT_DP_MST) {