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

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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@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230526235538.2230780-4-John.C.Harrison@Intel.com
This commit is contained in:
Michal Wajdeczko 2023-05-26 16:55:38 -07:00 committed by John Harrison
parent d9911020ca
commit a5606b94cd
3 changed files with 77 additions and 3 deletions
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1
drivers/gpu/drm/i915/Kconfig.debug
View File

@ -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

68
drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
View File

@ -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 @@ corrupted:
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);

11
drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
View File

@ -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 */