Re: [PATCH] drm/amdgpu: add ring buffer information in devcoredump

["Christian König" <christian.koenig@amd.com>]

Am 11.03.24 um 13:22 schrieb Sunil Khatri:
> Add relevant ringbuffer information such as
> rptr, wptr, ring name, ring size and also
> the ring contents for each ring on a gpu reset.
>
> Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c | 21 +++++++++++++++++++++
>   1 file changed, 21 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c
> index 6d059f853adc..1992760039da 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_reset.c
> @@ -215,6 +215,27 @@ amdgpu_devcoredump_read(char *buffer, loff_t offset, size_t count,
>   			   fault_info->status);
>   	}
>   
> +	drm_printf(&p, "Ring buffer information\n");
> +	for (int i = 0; i < coredump->adev->num_rings; i++) {
> +		int j = 0;
> +		struct amdgpu_ring *ring = coredump->adev->rings[i];
> +
> +		drm_printf(&p, "ring name: %s\n", ring->name);
> +		drm_printf(&p, "Rptr: 0x%llx Wptr: 0x%llx\n",
> +			   amdgpu_ring_get_rptr(ring) & ring->buf_mask,
> +			   amdgpu_ring_get_wptr(ring) & ring->buf_mask);

Don't apply the mask here. We do have some use cases where the rptr and 
wptr are outside the ring buffer.

> +		drm_printf(&p, "Ring size in dwords: %d\n",
> +			   ring->ring_size / 4);

Rather print the mask as additional value here.

> +		drm_printf(&p, "Ring contents\n");
> +		drm_printf(&p, "Offset \t Value\n");
> +
> +		while (j < ring->ring_size) {
> +			drm_printf(&p, "0x%x \t 0x%x\n", j, ring->ring[j/4]);
> +			j += 4;
> +		}

> +		drm_printf(&p, "Ring dumped\n");

That seems superfluous.

Regards,
Christian.

> +	}
> +
>   	if (coredump->reset_vram_lost)
>   		drm_printf(&p, "VRAM is lost due to GPU reset!\n");
>   	if (coredump->adev->reset_info.num_regs) {