[PATCH v4 3/8] drm/amdgpu: Fix SMU error failure

[Bjorn Helgaas]

On Wed, Sep 02, 2020 at 02:42:05PM -0400, Andrey Grodzovsky wrote:
> Wait for HW/PSP initiated ASIC reset to complete before
> starting the recovery operations.
> 
> v2: Remove typo
> 
> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 22 ++++++++++++++++++++--
>  1 file changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index e999f1f..412d07e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -4838,14 +4838,32 @@ pci_ers_result_t amdgpu_pci_slot_reset(struct pci_dev *pdev)
>  {
>  	struct drm_device *dev = pci_get_drvdata(pdev);
>  	struct amdgpu_device *adev = drm_to_adev(dev);
> -	int r;
> +	int r, i;
>  	bool vram_lost;
> +	u32 memsize;
>  
>  	DRM_INFO("PCI error: slot reset callback!!\n");
>  
> +	/* wait for asic to come out of reset */

I know it's totally OCD, but it is a minor speed bump to read "asic"
here and "ASIC" in the commit log above and the new comment below.

> +	msleep(500);
> +
>  	pci_restore_state(pdev);
>  
> -	adev->in_pci_err_recovery = true;
> +	/* confirm  ASIC came out of reset */
> +	for (i = 0; i < adev->usec_timeout; i++) {
> +		memsize = amdgpu_asic_get_config_memsize(adev);
> +
> +		if (memsize != 0xffffffff)

I guess this is a spot where you actually depend on an MMIO read
returning 0xffffffff because adev->in_pci_err_recovery is false at
this point, so amdgpu_mm_rreg() will actually *do* the MMIO read
instead of returning 0.  Right?

> +			break;
> +		udelay(1);
> +	}
> +	if (memsize == 0xffffffff) {
> +		r = -ETIME;
> +		goto out;
> +	}
> +
> +	/* TODO Call amdgpu_pre_asic_reset instead */
> +	adev->in_pci_err_recovery = true;	
>  	r = amdgpu_device_ip_suspend(adev);
>  	adev->in_pci_err_recovery = false;
>  	if (r)
> -- 
> 2.7.4
>