[PATCH] drm/amdgpu: Move reset domain locking in DPC handler

[Chen, Guchun]

It's in amdgpu_pci_resume.

Andrey, shall we modify the code accordingly in amdgpu_pci_resume as well? Otherwise, an unset/unlock leak will happen when pci_channel_state != pci_channel_io_frozen.

Regards,
Guchun

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Christian König
Sent: Thursday, April 14, 2022 2:40 PM
To: Grodzovsky, Andrey <Andrey.Grodzovsky at amd.com>; amd-gfx at lists.freedesktop.org
Cc: Antonovitch, Anatoli <Anatoli.Antonovitch at amd.com>
Subject: Re: [PATCH] drm/amdgpu: Move reset domain locking in DPC handler



Am 13.04.22 um 21:31 schrieb Andrey Grodzovsky:
> Lock reset domain unconditionally because on resume we unlock it 
> unconditionally.
> This solved mutex deadlock when handling both FATAL and non FATAL PCI 
> errors one after another.
>
> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 14 +++++++-------
>   1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 1cc488a767d8..c65f25e3a0fc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -5531,18 +5531,18 @@ pci_ers_result_t 
> amdgpu_pci_error_detected(struct pci_dev *pdev, pci_channel_sta
>   
>   	adev->pci_channel_state = state;
>   
> +	/*
> +	 * Locking adev->reset_domain->sem will prevent any external access
> +	 * to GPU during PCI error recovery
> +	 */
> +	amdgpu_device_lock_reset_domain(adev->reset_domain);
> +	amdgpu_device_set_mp1_state(adev);
> +
>   	switch (state) {
>   	case pci_channel_io_normal:
>   		return PCI_ERS_RESULT_CAN_RECOVER;

BTW: Where are we unlocking that again?

>   	/* Fatal error, prepare for slot reset */
>   	case pci_channel_io_frozen:
> -		/*
> -		 * Locking adev->reset_domain->sem will prevent any external access
> -		 * to GPU during PCI error recovery
> -		 */
> -		amdgpu_device_lock_reset_domain(adev->reset_domain);
> -		amdgpu_device_set_mp1_state(adev);
> -
>   		/*
>   		 * Block any work scheduling as we do for regular GPU reset
>   		 * for the duration of the recovery