From: pding <Pixel.Ding@amd.com>
Date: Mon, 23 Oct 2017 16:31:04 +0800
Subject: drm/amdgpu: avoid soft lockup when waiting for RLC serdes (v2)
Git-commit: 1366b2d01654d2028cba64109ad1bffb8afbef73
Patch-mainline: v4.16-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Normally all waiting get timeout if there's one.
Release the lock and return immediately when timeout happens.

v2:
 - set the se_sh to broadcase before return

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: pding <Pixel.Ding@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c |    8 ++++++++
 drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c |    8 ++++++++
 2 files changed, 16 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
@@ -3851,6 +3851,14 @@ static void gfx_v8_0_wait_for_rlc_serdes
 					break;
 				udelay(1);
 			}
+			if (k == adev->usec_timeout) {
+				gfx_v8_0_select_se_sh(adev, 0xffffffff,
+						      0xffffffff, 0xffffffff);
+				mutex_unlock(&adev->grbm_idx_mutex);
+				DRM_INFO("Timeout wait for RLC serdes %u,%u\n",
+					 i, j);
+				return;
+			}
 		}
 	}
 	gfx_v8_0_select_se_sh(adev, 0xffffffff, 0xffffffff, 0xffffffff);
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
@@ -1645,6 +1645,14 @@ static void gfx_v9_0_wait_for_rlc_serdes
 					break;
 				udelay(1);
 			}
+			if (k == adev->usec_timeout) {
+				gfx_v9_0_select_se_sh(adev, 0xffffffff,
+						      0xffffffff, 0xffffffff);
+				mutex_unlock(&adev->grbm_idx_mutex);
+				DRM_INFO("Timeout wait for RLC serdes %u,%u\n",
+					 i, j);
+				return;
+			}
 		}
 	}
 	gfx_v9_0_select_se_sh(adev, 0xffffffff, 0xffffffff, 0xffffffff);