From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga04.intel.com ([192.55.52.120]:1667 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754272AbeDCH01 (ORCPT ); Tue, 3 Apr 2018 03:26:27 -0400 From: Jani Nikula To: Dhinakaran Pandiyan , intel-gfx@lists.freedesktop.org Cc: Dhinakaran Pandiyan , Ville =?utf-8?B?U3lyasOkbMOk?= , stable@vger.kernel.org Subject: Re: [stable:v4.15] drm/i915/dp: Write to SET_POWER dpcd to enable MST hub. In-Reply-To: <20180329195150.26186-1-dhinakaran.pandiyan@intel.com> References: <20180329195150.26186-1-dhinakaran.pandiyan@intel.com> Date: Tue, 03 Apr 2018 10:27:16 +0300 Message-ID: <878ta4bvhn.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: stable-owner@vger.kernel.org List-ID: DK, please start stable backport commit messages with: commit b1e314462bba76660eec62760bb2e87f28f58866 upstream. Referencing the upstream commit. BR, Jani. On Thu, 29 Mar 2018, Dhinakaran Pandiyan wrote: > If bios sets up an MST output and hardware state readout code sees this is > an SST configuration, when disabling the encoder we end up calling > ->post_disable_dp() hook instead of the MST version. Consequently, we write > to the DP_SET_POWER dpcd to set it D3 state. Further along when we try > enable the encoder in MST mode, POWER_UP_PHY transaction fails to power up > the MST hub. This results in continuous link training failures which keep > the system busy delaying boot. We could identify bios MST boot discrepancy > and handle it accordingly but a simple way to solve this is to write to the > DP_SET_POWER dpcd for MST too. > > v2: Rebased on stable/linux-4.15.y and fixed minor conflict. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105470 > Cc: Ville Syrjälä > Cc: Jani Nikula > Reviewed-by: Ville Syrjälä > Reported-by: Laura Abbott > Cc: # 4.15+ > Fixes: 5ea2355a100a ("drm/i915/mst: Use MST sideband message transactions for dpms control") > Tested-by: Laura Abbott > Signed-off-by: Dhinakaran Pandiyan > Signed-off-by: Jani Nikula > Link: https://patchwork.freedesktop.org/patch/msgid/20180314054825.1718-1-dhinakaran.pandiyan@intel.com > (cherry picked from commit ad260ab32a4d94fa974f58262f8000472d34fd5b) > Signed-off-by: Dhinakaran Pandiyan > --- > drivers/gpu/drm/i915/intel_ddi.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c > index 58a3755544b2..38e53d6b8127 100644 > --- a/drivers/gpu/drm/i915/intel_ddi.c > +++ b/drivers/gpu/drm/i915/intel_ddi.c > @@ -2208,8 +2208,7 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder, > intel_prepare_dp_ddi_buffers(encoder); > > intel_ddi_init_dp_buf_reg(encoder); > - if (!is_mst) > - intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON); > + intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON); > intel_dp_start_link_train(intel_dp); > if (port != PORT_A || INTEL_GEN(dev_priv) >= 9) > intel_dp_stop_link_train(intel_dp); > @@ -2294,19 +2293,12 @@ static void intel_ddi_post_disable_dp(struct intel_encoder *encoder, > struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); > struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base); > struct intel_dp *intel_dp = &dig_port->dp; > - /* > - * old_crtc_state and old_conn_state are NULL when called from > - * DP_MST. The main connector associated with this port is never > - * bound to a crtc for MST. > - */ > - bool is_mst = !old_crtc_state; > > /* > * Power down sink before disabling the port, otherwise we end > * up getting interrupts from the sink on detecting link loss. > */ > - if (!is_mst) > - intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF); > + intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF); > > intel_disable_ddi_buf(encoder); -- Jani Nikula, Intel Open Source Technology Center