Commit 248b0616 authored Oct 01, 2021 by Guchun Chen Committed by Alex Deucher Oct 05, 2021

drm/amdgpu: handle the case of pci_channel_io_frozen only in amdgpu_pci_resume



In current code, when a PCI error state pci_channel_io_normal is detectd,
it will report PCI_ERS_RESULT_CAN_RECOVER status to PCI driver, and PCI
driver will continue the execution of PCI resume callback report_resume by
pci_walk_bridge, and the callback will go into amdgpu_pci_resume
finally, where write lock is releasd unconditionally without acquiring
such lock first. In this case, a deadlock will happen when other threads
start to acquire the read lock.

To fix this, add a member in amdgpu_device strucutre to cache
pci_channel_state, and only continue the execution in amdgpu_pci_resume
when it's pci_channel_io_frozen.

Fixes: c9a6b82f ("drm/amdgpu: Implement DPC recovery")
Suggested-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

parent 714d9e45

drivers/gpu/drm/amd/amdgpu/amdgpu.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1087,6 +1087,7 @@ struct amdgpu_device {

		bool no_hw_access;
		struct pci_saved_state *pci_state;
		pci_channel_state_t pci_channel_state;

		struct amdgpu_reset_control *reset_cntl;
		};

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -5399,6 +5399,8 @@ pci_ers_result_t amdgpu_pci_error_detected(struct pci_dev *pdev, pci_channel_sta
		return PCI_ERS_RESULT_DISCONNECT;
		}

		adev->pci_channel_state = state;

		switch (state) {
		case pci_channel_io_normal:
		return PCI_ERS_RESULT_CAN_RECOVER;
		@@ -5541,6 +5543,10 @@ void amdgpu_pci_resume(struct pci_dev *pdev)

		DRM_INFO("PCI error: resume callback!!\n");

		/* Only continue execution for the case of pci_channel_io_frozen */
		if (adev->pci_channel_state != pci_channel_io_frozen)
		return;

		for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
		struct amdgpu_ring *ring = adev->rings[i];