drm/amd/display: Add support for hw_state logging via debugfs

[Why]

We have logging methods for printing hardware state for newer ASICs
but no way to trigger the log output.

[How]

Add support for triggering the output via writing to a debugfs file
entry. Log output currently goes into dmesg for convenience, but
accessing via a read should be possible later.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Jordan Lazare <Jordan.Lazare@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index 8403b6a9a77b..86b63ce1dbf6 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -336,14 +336,28 @@ bool dm_helpers_dp_mst_send_payload_allocation(
 }
 
 void dm_dtn_log_begin(struct dc_context *ctx)
-{}
+{
+	pr_info("[dtn begin]\n");
+}
 
 void dm_dtn_log_append_v(struct dc_context *ctx,
-		const char *pMsg, ...)
-{}
+		const char *msg, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, msg);
+	vaf.fmt = msg;
+	vaf.va = &args;
+
+	pr_info("%pV", &vaf);
+	va_end(args);
+}
 
 void dm_dtn_log_end(struct dc_context *ctx)
-{}
+{
+	pr_info("[dtn end]\n");
+}
 
 bool dm_helpers_dp_mst_start_top_mgr(
 		struct dc_context *ctx,