[Intel-gfx] [PATCH] drm/i915: Add debugfs file to dump entire logical context

Volkin, Bradley D bradley.d.volkin at intel.com
Fri Oct 31 17:18:59 CET 2014


On Thu, Oct 30, 2014 at 04:03:23PM -0700, armin.c.reese at intel.com wrote:
> From: Armin Reese <armin.c.reese at intel.com>
> 
> The new 'i915_context_dump' file generates a hex dump of the
> entire logical context DRM object.  It is useful for
> validating the contents of the default context set up by
> the golden state batch buffer.

This patch needs a changelog providing brief descriptions of what
has changed in each new version that you send.

> 
> Signed-off-by: Armin Reese <armin.c.reese at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c | 92 ++++++++++++++++++++++++++++++-------
>  1 file changed, 76 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index a79f83c..7807c14 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -46,6 +46,11 @@ enum {
>  	PINNED_LIST,
>  };
>  
> +enum {
> +	LRC_CONTEXT_DUMP,

I think this should be something like REG_STATE_CONTEXT_DUMP or similar.
It better describes what we're actually dumping in this case.

> +	FULL_CONTEXT_DUMP,
> +};
> +
>  static const char *yesno(int v)
>  {
>  	return v ? "yes" : "no";
> @@ -120,6 +125,52 @@ static inline const char *get_global_flag(struct drm_i915_gem_object *obj)
>  }
>  
>  static void
> +dump_32_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
> +{
> +	struct page *page;
> +	size_t size; /* In bytes */
> +	size_t start_dword, end_dword, end_row_dword; /* In uint32_t offsets */
> +	int i, num_pages;
> +	uint32_t *obj_ptr;
> +
> +	if (i915_gem_object_get_pages(obj))
> +		return;
> +
> +	size = obj->base.size; /* In bytes */
> +	num_pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
> +
> +	for (i = 0; i < num_pages; i++) {
> +		page = i915_gem_object_get_page(obj, i);

I believe the preferred way to walk the list of pages is:

	struct sg_page_iter sg_iter;
	for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
		page = sg_page_iter_page(&sg_iter);

If we make this change, num_pages is no longer used.

> +		drm_clflush_pages(&page, 1);
> +
> +		start_dword = (i * PAGE_SIZE) / sizeof(uint32_t);
> +		end_dword = start_dword + (PAGE_SIZE / sizeof(uint32_t));
> +		if ((end_dword * sizeof(uint32_t)) > size)
> +			end_dword = size / sizeof(uint32_t);

The size of a GEM object is always a multiple of the page size, so you
can assume that it's safe to just dump the entirety of each page in the
object's page list. I think you can also use this fact to simplify the
looping below. And you might consider doing obj_ptr++ instead of the
bitwise 'and'.

Brad

> +
> +		obj_ptr = (uint32_t *)kmap_atomic(page);
> +
> +		while (start_dword < end_dword) {
> +			end_row_dword = start_dword + 8;
> +			if (end_row_dword > end_dword)
> +				end_row_dword = end_dword;
> +			seq_printf(m, "0x%08lx:  ",
> +					start_dword * sizeof(uint32_t));
> +			while (start_dword < end_row_dword) {
> +				seq_printf(m, "0x%08x ",
> +						*(obj_ptr +
> +						(start_dword &
> +						 (PAGE_SIZE - 1))));
> +				start_dword++;
> +			}
> +			seq_puts(m, "\n");
> +		}
> +
> +		kunmap_atomic(obj_ptr);
> +	}
> +}
> +
> +static void
>  describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
>  {
>  	struct i915_vma *vma;
> @@ -1773,9 +1824,10 @@ static int i915_context_status(struct seq_file *m, void *unused)
>  	return 0;
>  }
>  
> -static int i915_dump_lrc(struct seq_file *m, void *unused)
> +static int i915_dump_lrc(struct seq_file *m, void *data)
>  {
>  	struct drm_info_node *node = (struct drm_info_node *) m->private;
> +	uintptr_t dump_flag = (uintptr_t) node->info_ent->data;
>  	struct drm_device *dev = node->minor->dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct intel_engine_cs *ring;
> @@ -1795,24 +1847,31 @@ static int i915_dump_lrc(struct seq_file *m, void *unused)
>  		for_each_ring(ring, dev_priv, i) {
>  			struct drm_i915_gem_object *ctx_obj = ctx->engine[i].state;
>  
> -			if (ring->default_context == ctx)
> +			if ((ring->default_context == ctx) &&
> +				(dump_flag == LRC_CONTEXT_DUMP))
>  				continue;
>  
>  			if (ctx_obj) {
> -				struct page *page = i915_gem_object_get_page(ctx_obj, 1);
> -				uint32_t *reg_state = kmap_atomic(page);
> -				int j;
> -
> -				seq_printf(m, "CONTEXT: %s %u\n", ring->name,
> -						intel_execlists_ctx_id(ctx_obj));
> -
> -				for (j = 0; j < 0x600 / sizeof(u32) / 4; j += 4) {
> -					seq_printf(m, "\t[0x%08lx] 0x%08x 0x%08x 0x%08x 0x%08x\n",
> -					i915_gem_obj_ggtt_offset(ctx_obj) + 4096 + (j * 4),
> -					reg_state[j], reg_state[j + 1],
> -					reg_state[j + 2], reg_state[j + 3]);
> +				if (dump_flag == LRC_CONTEXT_DUMP) {
> +					struct page *page = i915_gem_object_get_page(ctx_obj, 1);
> +					uint32_t *reg_state = kmap_atomic(page);
> +					int j;
> +
> +					seq_printf(m, "CONTEXT: %s %u\n", ring->name,
> +							intel_execlists_ctx_id(ctx_obj));
> +
> +					for (j = 0; j < 0x600 / sizeof(u32) / 4; j += 4) {
> +						seq_printf(m, "\t[0x%08lx] 0x%08x 0x%08x 0x%08x 0x%08x\n",
> +						i915_gem_obj_ggtt_offset(ctx_obj) + 4096 + (j * 4),
> +						reg_state[j], reg_state[j + 1],
> +						reg_state[j + 2], reg_state[j + 3]);
> +					}
> +					kunmap_atomic(reg_state);
> +				} else if (dump_flag == FULL_CONTEXT_DUMP) {
> +					seq_printf(m, "Full Context Dump: %s %u\n", ring->name,
> +							intel_execlists_ctx_id(ctx_obj));
> +					dump_32_obj(m, ctx_obj);
>  				}
> -				kunmap_atomic(reg_state);
>  
>  				seq_putc(m, '\n');
>  			}
> @@ -4187,7 +4246,8 @@ static const struct drm_info_list i915_debugfs_list[] = {
>  	{"i915_opregion", i915_opregion, 0},
>  	{"i915_gem_framebuffer", i915_gem_framebuffer_info, 0},
>  	{"i915_context_status", i915_context_status, 0},
> -	{"i915_dump_lrc", i915_dump_lrc, 0},
> +	{"i915_context_dump", i915_dump_lrc, 0, (void *)FULL_CONTEXT_DUMP},
> +	{"i915_dump_lrc", i915_dump_lrc, 0, (void *)LRC_CONTEXT_DUMP},
>  	{"i915_execlists", i915_execlists, 0},
>  	{"i915_gen6_forcewake_count", i915_gen6_forcewake_count_info, 0},
>  	{"i915_swizzle_info", i915_swizzle_info, 0},
> -- 
> 1.9.1
> 
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