From: Evan Quan Date: Wed, 6 Nov 2019 04:40:12 +0000 (+0800) Subject: drm/amd/powerplay: fix deadlock on setting power_dpm_force_performance_level X-Git-Tag: v5.5-rc1~128^2~11^2~22 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cf3fde893d3a86fe5275061fbf80d67271d2d0cf;p=thirdparty%2Fkernel%2Flinux.git 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. Signed-off-by: Evan Quan Reviewed-by: Feifei Xu Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c index 85ba341e5d199..66faea66a8e92 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; }