From ed8d60f450d3db4c4dbb25eddc8f106cbab4bd1c Mon Sep 17 00:00:00 2001 From: Matt Roper Date: Thu, 28 Jan 2016 15:09:37 -0800 Subject: [PATCH] drm/i915: Check DDI max lanes after applying BXT workaround MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit In commit bfb9faab8 we added a workaround for some BXT BIOS that fail to properly initialize the DDI_A_4_LANES bit of the control register (4 lanes is the only valid configuration on BXT since there is no DDI E to share with). A recent patch added some additional checks on this register bit before the workaround gets applied; this breaks eDP on BXT in some settings. Some minor code shuffling is all we need to restore the workaround. Cc: Ville Syrjälä Fixes: 7cd87cb80 ("drm/i915: Check max number of lanes when registering DDI ports") Signed-off-by: Matt Roper Link: http://patchwork.freedesktop.org/patch/msgid/1454022577-834-1-git-send-email-matthew.d.roper@intel.com Reviewed-by: Ville Syrjälä --- drivers/gpu/drm/i915/intel_ddi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index 1f9a3687b540..6d5b09f2a8a6 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -3281,7 +3281,6 @@ void intel_ddi_init(struct drm_device *dev, enum port port) intel_dig_port->saved_port_bits = I915_READ(DDI_BUF_CTL(port)) & (DDI_BUF_PORT_REVERSAL | DDI_A_4_LANES); - intel_dig_port->max_lanes = max_lanes; /* * Bspec says that DDI_A_4_LANES is the only supported configuration @@ -3294,9 +3293,12 @@ void intel_ddi_init(struct drm_device *dev, enum port port) if (!(intel_dig_port->saved_port_bits & DDI_A_4_LANES)) { DRM_DEBUG_KMS("BXT BIOS forgot to set DDI_A_4_LANES for port A; fixing\n"); intel_dig_port->saved_port_bits |= DDI_A_4_LANES; + max_lanes = 4; } } + intel_dig_port->max_lanes = max_lanes; + intel_encoder->type = INTEL_OUTPUT_UNKNOWN; intel_encoder->crtc_mask = (1 << 0) | (1 << 1) | (1 << 2); intel_encoder->cloneable = 0; -- 2.20.1