[Intel-gfx] [RFC 1/2] drm/i915: Add a debugfs file to dump full ring contexts

[Arun Siluvery]

From: Armin Reese <armin.c.reese at intel.com>

A 'cat' of the debugfs file i915_dump_lrc, dumps only the first 0x600 bytes
of each ring's register state context. It does not provide information about
the remaining portion of the register state context.
This patch adds a new file i915_context_dump which displays the ring's hws page
along with the ring's full register state context. Having this data in its
entirety will definitely help in debugging GPU hang issues to understand the
state of context.

v1: Original patch
v2: reuse i915_dump_lrc_obj instead of creating new fn.

Signed-off-by: Armin Reese <armin.c.reese at intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 73 ++++++++++++++++++++++++++-----------
 1 file changed, 52 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 7a28de5..9c5c42d 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,	/* First 1536 bytes of register state ctx */
+	FULL_CONTEXT_DUMP,	/* Full context (HW status + reg state ctx) */
+};
+
 static const char *yesno(int v)
 {
 	return v ? "yes" : "no";
@@ -1969,18 +1974,16 @@ static int i915_context_status(struct seq_file *m, void *unused)
 
 static void i915_dump_lrc_obj(struct seq_file *m,
 			      struct intel_engine_cs *ring,
-			      struct drm_i915_gem_object *ctx_obj)
+			      struct drm_i915_gem_object *ctx_obj,
+			      unsigned long dump_type)
 {
 	struct page *page;
+	struct sg_page_iter sg_iter;
 	uint32_t *reg_state;
+	int i;
 	int j;
 	unsigned long ggtt_offset = 0;
-
-	if (ctx_obj == NULL) {
-		seq_printf(m, "Context on %s with no gem object\n",
-			   ring->name);
-		return;
-	}
+	int hws_page_index;
 
 	seq_printf(m, "CONTEXT: %s %u\n", ring->name,
 		   intel_execlists_ctx_id(ctx_obj));
@@ -1995,29 +1998,44 @@ static void i915_dump_lrc_obj(struct seq_file *m,
 		return;
 	}
 
-	page = i915_gem_object_get_page(ctx_obj, LRC_STATE_PN);
-	if (!WARN_ON(page == NULL)) {
-		reg_state = kmap_atomic(page);
+	i = 0;
+	hws_page_index = LRC_PPHWSP_PN;
+	for_each_sg_page(ctx_obj->pages->sgl, &sg_iter,
+			 ctx_obj->pages->nents, 0) {
+		if (dump_type == LRC_CONTEXT_DUMP) {
+			if (i < hws_page_index) {
+				++i;
+				continue;
+			} else if (i > hws_page_index)
+				break;
+		}
 
-		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",
-				   ggtt_offset + 4096 + (j * 4),
-				   reg_state[j], reg_state[j + 1],
-				   reg_state[j + 2], reg_state[j + 3]);
+		page = sg_page_iter_page(&sg_iter);
+		if (!WARN_ON(page == NULL)) {
+			reg_state = kmap_atomic(page);
+
+			for (j = 0; j < PAGE_SIZE / sizeof(u32); j += 4) {
+				seq_printf(m, "\t[0x%08lx] 0x%08x 0x%08x 0x%08x 0x%08x\n",
+					   ggtt_offset + 4096 + (j * 4),
+					   reg_state[j], reg_state[j + 1],
+					   reg_state[j + 2], reg_state[j + 3]);
+			}
+			kunmap_atomic(reg_state);
 		}
-		kunmap_atomic(reg_state);
+		++i;
 	}
 
 	seq_putc(m, '\n');
 }
 
-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;
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_engine_cs *ring;
 	struct intel_context *ctx;
+	uintptr_t dump_type = (uintptr_t) node->info_ent->data;
 	int ret, i;
 
 	if (!i915.enable_execlists) {
@@ -2031,9 +2049,21 @@ static int i915_dump_lrc(struct seq_file *m, void *unused)
 
 	list_for_each_entry(ctx, &dev_priv->context_list, link) {
 		for_each_ring(ring, dev_priv, i) {
-			if (ring->default_context != ctx)
-				i915_dump_lrc_obj(m, ring,
-						  ctx->engine[i].state);
+			if (ring->default_context != ctx) {
+				struct drm_i915_gem_object *ctx_obj =
+					ctx->engine[i].state;
+				if (ctx_obj && ctx->file_priv) {
+					seq_printf(m, "CONTEXT: %s (PID: %u, UH:%d)\n",
+						   ring->name,
+						   pid_nr(ctx->file_priv->file->pid),
+						   ctx->user_handle);
+					i915_dump_lrc_obj(m, ring,
+							  ctx_obj,
+							  dump_type);
+				} else
+					seq_printf(m, "Context on %s with no gem object\n",
+						   ring->name);
+			}
 		}
 	}
 
@@ -5189,7 +5219,8 @@ 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_dump_lrc", i915_dump_lrc, 0, (void *) LRC_CONTEXT_DUMP},
+	{"i915_context_dump", i915_dump_lrc, 0, (void *)FULL_CONTEXT_DUMP},
 	{"i915_execlists", i915_execlists, 0},
 	{"i915_forcewake_domains", i915_forcewake_domains, 0},
 	{"i915_swizzle_info", i915_swizzle_info, 0},
-- 
1.9.1