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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Ville Syrjala <ville.syrjala@linux.intel.com>,
        Imre Deak <imre.deak@intel.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Cooper Chiou <cooper.chiou@intel.com>,
        William Tseng <william.tseng@intel.com>,
        Lee Shawn C <shawn.c.lee@intel.com>,
        Jani Nikula <jani.nikula@intel.com>
Subject: [PATCH 5.14 049/168] drm/i915/dp: return proper DPRX link training result
Date:   Mon, 20 Sep 2021 18:43:07 +0200
Message-Id: <20210920163923.250441951@linuxfoundation.org>
In-Reply-To: <20210920163921.633181900@linuxfoundation.org>
References: <20210920163921.633181900@linuxfoundation.org>
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From: Lee Shawn C <shawn.c.lee@intel.com>

commit 9af4bf2171c1a9e3f2ebb21140c0e34e60b2a22a upstream.

After DPRX link training, intel_dp_link_train_phy() did not
return the training result properly. If link training failed,
i915 driver would not run into link train fallback function.
And no hotplug uevent would be received by user space application.

Fixes: b30edfd8d0b4 ("drm/i915: Switch to LTTPR non-transparent mode link training")
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Cooper Chiou <cooper.chiou@intel.com>
Cc: William Tseng <william.tseng@intel.com>
Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210706152541.25021-1-shawn.c.lee@intel.com
(cherry picked from commit dab1b47e57e053b2a02c22ead8e7449f79961335)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/i915/display/intel_dp_link_training.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -848,7 +848,7 @@ intel_dp_link_train_all_phys(struct inte
 	}
 
 	if (ret)
-		intel_dp_link_train_phy(intel_dp, crtc_state, DP_PHY_DPRX);
+		ret = intel_dp_link_train_phy(intel_dp, crtc_state, DP_PHY_DPRX);
 
 	if (intel_dp->set_idle_link_train)
 		intel_dp->set_idle_link_train(intel_dp, crtc_state);