Commit a5606b94 authored by Michal Wajdeczko's avatar Michal Wajdeczko Committed by John Harrison
Browse files

drm/i915/guc: Track all sent actions to GuC 



For easier debug of any unexpected error responses from GuC that
might be related to non-blocking fast requests, track action code (and
stack if under DEBUG_GUC config) for every H2G request.

Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: default avatarJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: default avatarJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230526235538.2230780-4-John.C.Harrison@Intel.com
parent d9911020

drivers/gpu/drm/i915/Kconfig.debug

+1 −0
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ config DRM_I915_SW_FENCE_CHECK_DAG 
config DRM_I915_DEBUG_GUC

	bool "Enable additional driver debugging for GuC"

	depends on DRM_I915

	select STACKDEPOT

	default n

	help

	  Choose this option to turn on extra driver debugging that may affect

drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c

+65 −3
Original line number Diff line number Diff line
@@ -376,6 +376,24 @@ void intel_guc_ct_disable(struct intel_guc_ct *ct) 
	}

}



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)

static void ct_track_lost_and_found(struct intel_guc_ct *ct, u32 fence, u32 action)

{

	unsigned int lost = fence % ARRAY_SIZE(ct->requests.lost_and_found);

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GUC)

	unsigned long entries[SZ_32];

	unsigned int n;



	n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);



	/* May be called under spinlock, so avoid sleeping */

	ct->requests.lost_and_found[lost].stack = stack_depot_save(entries, n, GFP_NOWAIT);

#endif

	ct->requests.lost_and_found[lost].fence = fence;

	ct->requests.lost_and_found[lost].action = action;

}

#endif



static u32 ct_get_next_fence(struct intel_guc_ct *ct)

{

	/* For now it's trivial */
@@ -447,6 +465,11 @@ static int ct_write(struct intel_guc_ct *ct, 
	}

	GEM_BUG_ON(tail > size);



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)

	ct_track_lost_and_found(ct, fence,

				FIELD_GET(GUC_HXG_EVENT_MSG_0_ACTION, action[0]));

#endif



	/*

	 * make sure H2G buffer update and LRC tail update (if this triggering a

	 * submission) are visible before updating the descriptor tail
@@ -953,6 +976,43 @@ static int ct_read(struct intel_guc_ct *ct, struct ct_incoming_msg **msg) 
	return -EPIPE;

}



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)

static bool ct_check_lost_and_found(struct intel_guc_ct *ct, u32 fence)

{

	unsigned int n;

	char *buf = NULL;

	bool found = false;



	lockdep_assert_held(&ct->requests.lock);



	for (n = 0; n < ARRAY_SIZE(ct->requests.lost_and_found); n++) {

		if (ct->requests.lost_and_found[n].fence != fence)

			continue;

		found = true;



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GUC)

		buf = kmalloc(SZ_4K, GFP_NOWAIT);

		if (buf && stack_depot_snprint(ct->requests.lost_and_found[n].stack,

					       buf, SZ_4K, 0)) {

			CT_ERROR(ct, "Fence %u was used by action %#04x sent at\n%s",

				 fence, ct->requests.lost_and_found[n].action, buf);

			break;

		}

#endif

		CT_ERROR(ct, "Fence %u was used by action %#04x\n",

			 fence, ct->requests.lost_and_found[n].action);

		break;

	}

	kfree(buf);

	return found;

}

#else

static bool ct_check_lost_and_found(struct intel_guc_ct *ct, u32 fence)

{

	return false;

}

#endif



static int ct_handle_response(struct intel_guc_ct *ct, struct ct_incoming_msg *response)

{

	u32 len = FIELD_GET(GUC_CTB_MSG_0_NUM_DWORDS, response->msg[0]);
@@ -996,9 +1056,11 @@ static int ct_handle_response(struct intel_guc_ct *ct, struct ct_incoming_msg *r 
	if (!found) {

		CT_ERROR(ct, "Unsolicited response message: len %u, data %#x (fence %u, last %u)\n",

			 len, hxg[0], fence, ct->requests.last_fence);

		if (!ct_check_lost_and_found(ct, fence)) {

			list_for_each_entry(req, &ct->requests.pending, link)

				CT_ERROR(ct, "request %u awaits response\n",

					 req->fence);

		}

		err = -ENOKEY;

	}

	spin_unlock_irqrestore(&ct->requests.lock, flags);

drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h

+11 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 


#include <linux/interrupt.h>

#include <linux/spinlock.h>

#include <linux/stackdepot.h>

#include <linux/workqueue.h>

#include <linux/ktime.h>

#include <linux/wait.h>
@@ -81,6 +82,16 @@ struct intel_guc_ct { 


		struct list_head incoming; /* incoming requests */

		struct work_struct worker; /* handler for incoming requests */



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)

		struct {

			u16 fence;

			u16 action;

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GUC)

			depot_stack_handle_t stack;

#endif

		} lost_and_found[SZ_16];

#endif

	} requests;



	/** @stall_time: time of first time a CTB submission is stalled */