From: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
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: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx>
---
drivers/gpu/drm/i915/Kconfig.debug | 1 +
drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 68 ++++++++++++++++++++++-
drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h | 11 ++++
3 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
index 47e845353ffad..2d21930d55015 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -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
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
index 3a71bb582089e..4aa903be1317b 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
@@ -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);
- list_for_each_entry(req, &ct->requests.pending, link)
- CT_ERROR(ct, "request %u awaits response\n",
- req->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);
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
index 818415b64f4d1..58e42901ff498 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
@@ -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 */
--
2.39.1
