From: Adam Jackson Date: Thu, 21 Jul 2011 21:48:38 +0000 (-0400) Subject: drm/i915/dp: Don't turn CPT DP ports on too early X-Git-Tag: firefly_0821_release~3680^2~4714^2~10^2~9^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e85194641bec56179dcf5e1704ce5c6bf30340c6;p=firefly-linux-kernel-4.4.55.git drm/i915/dp: Don't turn CPT DP ports on too early The docs say the port has to come on in training pattern 1; at this point, though, ->DP is in normal mode. The intent here is to wait until the port is in fact sending data, but that doesn't happen since we've broken the sequence the hardware expects, and the vblank wait will time out and kvetch in the log. Signed-off-by: Adam Jackson Reviewed-by: Jesse Barnes Signed-off-by: Keith Packard --- diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 8aecb072466b..dcc7ae6d4141 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1334,10 +1334,16 @@ intel_dp_start_link_train(struct intel_dp *intel_dp) u32 reg; uint32_t DP = intel_dp->DP; - /* Enable output, wait for it to become active */ - I915_WRITE(intel_dp->output_reg, intel_dp->DP); - POSTING_READ(intel_dp->output_reg); - intel_wait_for_vblank(dev, intel_crtc->pipe); + /* + * On CPT we have to enable the port in training pattern 1, which + * will happen below in intel_dp_set_link_train. Otherwise, enable + * the port and wait for it to become active. + */ + if (!HAS_PCH_CPT(dev)) { + I915_WRITE(intel_dp->output_reg, intel_dp->DP); + POSTING_READ(intel_dp->output_reg); + intel_wait_for_vblank(dev, intel_crtc->pipe); + } /* Write the link configuration data */ intel_dp_aux_native_write(intel_dp, DP_LINK_BW_SET,