[Intel-gfx] [RFC 2/2] drm/i915: Skip continguous dwords which are zeros

[Arun Siluvery]

From: Peter Antoine <peter.antoine at intel.com>

To reduce the amount of data being output the dump removes continguous
zeros to try and reduce the dump size. Not all the pages of context
contain valid data so it helps to reduce dump output.

Signed-off-by: Peter Antoine <peter.antoine at intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 9c5c42d..11cdd2c 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1983,7 +1983,6 @@ static void i915_dump_lrc_obj(struct seq_file *m,
 	int i;
 	int j;
 	unsigned long ggtt_offset = 0;
-	int hws_page_index;
 
 	seq_printf(m, "CONTEXT: %s %u\n", ring->name,
 		   intel_execlists_ctx_id(ctx_obj));
@@ -1999,27 +1998,51 @@ static void i915_dump_lrc_obj(struct seq_file *m,
 	}
 
 	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) {
+			if (i < LRC_PPHWSP_PN) {
 				++i;
 				continue;
-			} else if (i > hws_page_index)
+			} else if (i > LRC_PPHWSP_PN)
 				break;
 		}
 
 		page = sg_page_iter_page(&sg_iter);
 		if (!WARN_ON(page == NULL)) {
+			int run_length = 0;
+			unsigned long page_offset = ggtt_offset + i*PAGE_SIZE;
+
 			reg_state = kmap_atomic(page);
 
+			seq_printf(m, "Context object Page: %d\n", i);
 			for (j = 0; j < PAGE_SIZE / sizeof(u32); j += 4) {
+				if (reg_state[j + 0] == 0 && reg_state[j + 1] == 0 &&
+				    reg_state[j + 2] == 0 && reg_state[j + 3] == 0) {
+					run_length += 4;
+					continue;
+				}
+
+				if (run_length > 0) {
+					seq_printf(m, "\t[0x%08lx - 0x%08lx]: 0x00000000\n",
+						   page_offset + (j * 4) - (run_length * 4),
+						   page_offset + (j * 4) - 1);
+
+					run_length = 0;
+				}
+
 				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],
+					   page_offset + (j * 4),
+					   reg_state[j + 0], reg_state[j + 1],
 					   reg_state[j + 2], reg_state[j + 3]);
 			}
+
+			if (run_length > 0) {
+				seq_printf(m, "\t[0x%08lx - 0x%08lx]: 0x00000000\n",
+					   page_offset + (j * 4) - (run_length * 4),
+					   page_offset + (j * 4) - 1);
+				run_length = 0;
+			}
 			kunmap_atomic(reg_state);
 		}
 		++i;
-- 
1.9.1