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From 78141a8d63f703a2b0cfd29654c6a884f971fb92 Mon Sep 17 00:00:00 2001
From: Evan Quan <evan.quan@amd.com>
Date: Wed, 6 Nov 2019 12:40:12 +0800
Subject: [PATCH 4354/4736] drm/amd/powerplay: fix deadlock on setting
power_dpm_force_performance_level
smu_enable_umd_pstate() will try to get the smu->mutex which was already
hold by its parent API smu_force_performance_level() on the call path.
Thus deadlock happens.
Change-Id: Ic4d3c7d06eb47eab2ea42b98f399cd95ab320f0c
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
---
drivers/gpu/drm/amd/powerplay/amdgpu_smu.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
index facc19cae7e5..c21fe7ac5df8 100644
--- a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
+++ b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
@@ -383,14 +383,25 @@ bool smu_clk_dpm_is_enabled(struct smu_context *smu, enum smu_clk_type clk_type)
return true;
}
-
+/**
+ * smu_dpm_set_power_gate - power gate/ungate the specific IP block
+ *
+ * @smu: smu_context pointer
+ * @block_type: the IP block to power gate/ungate
+ * @gate: to power gate if true, ungate otherwise
+ *
+ * This API uses no smu->mutex lock protection due to:
+ * 1. It is either called by other IP block(gfx/sdma/vcn/uvd/vce).
+ * This is guarded to be race condition free by the caller.
+ * 2. Or get called on user setting request of power_dpm_force_performance_level.
+ * Under this case, the smu->mutex lock protection is already enforced on
+ * the parent API smu_force_performance_level of the call path.
+ */
int smu_dpm_set_power_gate(struct smu_context *smu, uint32_t block_type,
bool gate)
{
int ret = 0;
- mutex_lock(&smu->mutex);
-
switch (block_type) {
case AMD_IP_BLOCK_TYPE_UVD:
ret = smu_dpm_set_uvd_enable(smu, gate);
@@ -408,8 +419,6 @@ int smu_dpm_set_power_gate(struct smu_context *smu, uint32_t block_type,
break;
}
- mutex_unlock(&smu->mutex);
-
return ret;
}
--
2.17.1
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