[Intel-gfx] [PATCH 09/14] drm/i915: New module param to control the size of buffer used for storing GuC firmware logs

[akash.goel at intel.com]

From: Akash Goel <akash.goel at intel.com>

On recieving the log buffer flush interrupt from GuC firmware, Driver
stores the snapshot of the log buffer in a local buffer, from which
Userspace can pull the logs. By default Driver store, up to, 4 snapshots
of the log buffer in a local buffer (managed by relay).
Added a new module (read only) param, 'guc_log_size', through which User
can specify the number of snapshots of log buffer to be stored in local
buffer. This can be used to ensure capturing of all boot time logs even
with high verbosity level.

v2: Rename module param to more apt name 'guc_log_buffer_nr'. (Nikula)

Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Akash Goel <akash.goel at intel.com>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 3 +--
 drivers/gpu/drm/i915/i915_params.c         | 5 +++++
 drivers/gpu/drm/i915/i915_params.h         | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index 5b44976..ec68a6d 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -1016,8 +1016,7 @@ static int guc_create_log_relay_file(struct intel_guc *guc)
 
 	/* Keep the size of sub buffers same as shared log buffer */
 	subbuf_size = guc->log.obj->base.size;
-	/* TODO: Decide based on the User's input */
-	n_subbufs = 4;
+	n_subbufs = i915.guc_log_buffer_nr
 
 	guc_log_relay_chan = relay_open("guc_log", log_dir,
 			subbuf_size, n_subbufs, &relay_callbacks, dev);
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 8b13bfa..d30c972 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -57,6 +57,7 @@ struct i915_params i915 __read_mostly = {
 	.enable_guc_loading = -1,
 	.enable_guc_submission = -1,
 	.guc_log_level = -1,
+	.guc_log_buffer_nr = 4,
 	.enable_dp_mst = true,
 	.inject_load_failure = 0,
 	.enable_dpcd_backlight = false,
@@ -214,6 +215,10 @@ module_param_named(guc_log_level, i915.guc_log_level, int, 0400);
 MODULE_PARM_DESC(guc_log_level,
 	"GuC firmware logging level (-1:disabled (default), 0-3:enabled)");
 
+module_param_named(guc_log_buffer_nr, i915.guc_log_buffer_nr, int, 0400);
+MODULE_PARM_DESC(guc_log_buffer_nr,
+	"Number of sub buffers to store GuC firmware logs (default: 4)");
+
 module_param_named_unsafe(enable_dp_mst, i915.enable_dp_mst, bool, 0600);
 MODULE_PARM_DESC(enable_dp_mst,
 	"Enable multi-stream transport (MST) for new DisplayPort sinks. (default: true)");
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 0ad020b..14ca855 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -48,6 +48,7 @@ struct i915_params {
 	int enable_guc_loading;
 	int enable_guc_submission;
 	int guc_log_level;
+	int guc_log_buffer_nr;
 	int use_mmio_flip;
 	int mmio_debug;
 	int edp_vswing;
-- 
1.9.2