Re: [igt-dev] [PATCH i-g-t] i915/gem_(linear, tiled)_blits: Randomise buffer contents

["Das, Nirmoy" <nirmoy.das@linux.intel.com>]

On 1/18/2023 2:10 PM, Nirmoy Das wrote:
> From: Chris Wilson <chris.p.wilson@intel.com>
>
> Currently, we use an incrementing value for the buffer contents,
> starting the next buffer from the final value of the last. This means
> that the value of corresponding dwords between two buffers is offset
> by a single bit. In order to differentiate between an error in copying
> between two buffers from single bit memory errors, we need to randomise
> the offset between those two buffers.
>
> Cc: Kamil Konieczny <kamil.konieczny@linux.intel.com>
> Signed-off-by: Chris Wilson <chris.p.wilson@intel.com>
> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
> ---
>   tests/i915/gem_linear_blits.c        | 7 ++-----
>   tests/i915/gem_render_linear_blits.c | 8 +++++---
>   tests/i915/gem_render_tiled_blits.c  | 8 +++++---
>   tests/i915/gem_tiled_blits.c         | 6 ++----
>   4 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/tests/i915/gem_linear_blits.c b/tests/i915/gem_linear_blits.c
> index d02751be9..fac25095f 100644
> --- a/tests/i915/gem_linear_blits.c
> +++ b/tests/i915/gem_linear_blits.c
> @@ -184,7 +184,6 @@ static void run_test(int fd, int count, bool do_relocs)
>   {
>   	uint32_t *handle, *start_val;
>   	uint64_t *offset, ahnd;
> -	uint32_t start = 0;
>   	int i;
>   
>   	ahnd = intel_allocator_open(fd, 0, do_relocs ?
> @@ -197,13 +196,11 @@ static void run_test(int fd, int count, bool do_relocs)
>   	start_val = handle + count;
>   
>   	for (i = 0; i < count; i++) {
> -		handle[i] = create_bo(fd, start);
> +		start_val[i] = rand();
> +		handle[i] = create_bo(fd, start_val[i]);
>   
>   		offset[i] = intel_allocator_alloc(ahnd, handle[i],
>   						  sizeof(linear), ALIGNMENT);
> -
> -		start_val[i] = start;
> -		start += 1024 * 1024 / 4;
>   	}
>   
>   	for (i = 0; i < count; i++) {
> diff --git a/tests/i915/gem_render_linear_blits.c b/tests/i915/gem_render_linear_blits.c
> index d40593c64..c2f2c0788 100644
> --- a/tests/i915/gem_render_linear_blits.c
> +++ b/tests/i915/gem_render_linear_blits.c
> @@ -79,7 +79,6 @@ static void run_test (int fd, int count)
>   	struct intel_bb *ibb;
>   	uint32_t *start_val;
>   	struct intel_buf *bufs;
> -	uint32_t start = 0;
>   	int i, j;
>   
>   	render_copy = igt_get_render_copyfunc(intel_get_drm_devid(fd));
> @@ -92,11 +91,14 @@ static void run_test (int fd, int count)
>   	start_val = malloc(sizeof(*start_val)*count);
>   
>   	for (i = 0; i < count; i++) {
> +		uint32_t val;
> +
>   		intel_buf_init(bops, &bufs[i], WIDTH, HEIGHT, 32, 0,
>   			       I915_TILING_NONE, I915_COMPRESSION_NONE);
> -		start_val[i] = start;
> +		val = rand();
> +		start_val[i] = val;
>   		for (j = 0; j < WIDTH*HEIGHT; j++)
> -			linear[j] = start++;
> +			linear[j] = val++;
>   		gem_write(fd, bufs[i].handle, 0, linear, sizeof(linear));
>   	}
>   
> diff --git a/tests/i915/gem_render_tiled_blits.c b/tests/i915/gem_render_tiled_blits.c
> index 52d67b768..eae06a332 100644
> --- a/tests/i915/gem_render_tiled_blits.c
> +++ b/tests/i915/gem_render_tiled_blits.c
> @@ -97,7 +97,6 @@ static void run_test (int fd, int count)
>   	struct intel_bb *ibb;
>   	uint32_t *start_val;
>   	struct intel_buf *bufs;
> -	uint32_t start = 0;
>   	int i, j;
>   	uint32_t devid;
>   
> @@ -127,18 +126,21 @@ static void run_test (int fd, int count)
>   
>   	for (i = 0; i < count; i++) {
>   		uint32_t tiling = I915_TILING_X + (random() & 1);
> +		uint32_t val;
>   		uint32_t *ptr;
>   
>   		intel_buf_init(bops, &bufs[i], WIDTH, HEIGHT, 32, 0,
>   			       tiling, I915_COMPRESSION_NONE);
> -		start_val[i] = start;
>   
>   		ptr = gem_mmap__gtt(fd, bufs[i].handle,
>   				    bufs[i].surface[0].size, PROT_WRITE);
>   		gem_set_domain(fd, bufs[i].handle,
>   			       I915_GEM_DOMAIN_GTT, I915_GEM_DOMAIN_GTT);
> +
> +		val = rand();
> +		start_val[i] = val;
>   		for (j = 0; j < WIDTH*HEIGHT; j++)
> -			ptr[j] = start++;
> +			ptr[j] = val++;
>   
>   		munmap(ptr, bufs[i].surface[0].size);
>   	}
> diff --git a/tests/i915/gem_tiled_blits.c b/tests/i915/gem_tiled_blits.c
> index cc44d0f10..5e7ed0c4e 100644
> --- a/tests/i915/gem_tiled_blits.c
> +++ b/tests/i915/gem_tiled_blits.c
> @@ -128,7 +128,6 @@ static void run_test(int fd, int count)
>   	struct buf_ops *bops;
>   	struct intel_buf **bo;
>   	uint32_t *bo_start_val;
> -	uint32_t start = 0;
>   	int i;
>   
>   	bops = buf_ops_create(fd);
> @@ -138,9 +137,8 @@ static void run_test(int fd, int count)
>   	bo_start_val = malloc(sizeof(uint32_t)*count);
>   
>   	for (i = 0; i < count; i++) {
> -		bo[i] = create_bo(bops, ibb, start);
> -		bo_start_val[i] = start;
> -		start += 1024 * 1024 / 4;
> +		bo_start_val[i] = rand();
> +		bo[i] = create_bo(bops, ibb, bo_start_val[i]);
>   	}
>   
>   	for (i = 0; i < count + 1; i++) {