[PATCH 3/7] drm/amdgpu: avoid soft lockup when waiting for RLC serdes

[Pixel Ding]

From: pding <Pixel.Ding at amd.com>

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

Signed-off-by: pding <Pixel.Ding at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c | 6 ++++++
 drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
index fd38cb1..61753a3 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
@@ -3842,6 +3842,12 @@ static void gfx_v8_0_wait_for_rlc_serdes(struct amdgpu_device *adev)
 					break;
 				udelay(1);
 			}
+			if (k == adev->usec_timeout) {
+				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);
diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
index 50124ab..a2c67f6 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
@@ -1628,6 +1628,12 @@ static void gfx_v9_0_wait_for_rlc_serdes(struct amdgpu_device *adev)
 					break;
 				udelay(1);
 			}
+			if (k == adev->usec_timeout) {
+				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);
-- 
2.9.5