From 3d5f28824d48fcfc9636075c5074baed88a5e71a Mon Sep 17 00:00:00 2001
From: David Francis <David.Francis@amd.com>
Date: Mon, 20 Jul 2026 15:44:06 -0400
Subject: [PATCH] drm/amdgpu: Add trace events for pid register/deregister

Some debugging applications need to track when a process starts
or stops using the amdgpu driver. For those processes, add ftrace
events that track when a amdgpu_vm task info is changed or destroyed.

v2: Deregister in fini, not destroy.

v3: Also report render minor and major

cc: Sunil Khatri <Sunil.Khatri@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: David Francis <David.Francis@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 33 +++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c    | 26 ++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
index 09dd3174d505..66f4a1872913 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
@@ -730,6 +730,39 @@ TRACE_EVENT(amdgpu_userq_state_changed,
 		      __entry->client_id, __entry->queue_type, __entry->doorbell_index, __entry->to)
 );
 
+TRACE_EVENT(amdgpu_register_pid,
+	    TP_PROTO(uint32_t pid, int major, int minor),
+	    TP_ARGS(pid, major, minor),
+	    TP_STRUCT__entry(
+			__field(u32, pid)
+			__field(int, major)
+			__field(int, minor)
+	    ),
+	    TP_fast_assign(
+			__entry->pid = pid;
+			__entry->major = major;
+			__entry->minor = minor;
+	    ),
+	    TP_printk("amdgpu register pid %d render %d:%d",
+		      __entry->pid, __entry->major, __entry->minor)
+);
+TRACE_EVENT(amdgpu_deregister_pid,
+	    TP_PROTO(uint32_t pid, int major, int minor),
+	    TP_ARGS(pid, major, minor),
+	    TP_STRUCT__entry(
+			__field(u32, pid)
+			__field(int, major)
+			__field(int, minor)
+	    ),
+	    TP_fast_assign(
+			__entry->pid = pid;
+			__entry->major = major;
+			__entry->minor = minor;
+	    ),
+	    TP_printk("amdgpu deregister pid %d render %d:%d",
+		      __entry->pid, __entry->major, __entry->minor)
+);
+
 #undef AMDGPU_JOB_GET_TIMELINE_NAME
 #endif
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 36f6dcd063fe..6b210f7af57b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -33,6 +33,7 @@
 
 #include <drm/amdgpu_drm.h>
 #include <drm/drm_drv.h>
+#include <drm/drm_ioctl.h>
 #include <drm/ttm/ttm_tt.h>
 #include <drm/drm_exec.h>
 #include "amdgpu.h"
@@ -2563,6 +2564,12 @@ static int amdgpu_vm_create_task_info(struct amdgpu_vm *vm)
 	return 0;
 }
 
+static void amdgpu_vm_render_devt(struct amdgpu_device *adev, int *major, int *minor)
+{
+	*major = DRM_MAJOR;
+	*minor = adev_to_drm(adev)->render->index;
+}
+
 /**
  * amdgpu_vm_set_task_info - Sets VMs task info.
  *
@@ -2576,6 +2583,18 @@ void amdgpu_vm_set_task_info(struct amdgpu_vm *vm)
 	if (vm->task_info->task.pid == current->pid)
 		return;
 
+	if (vm->root.bo) {
+		struct amdgpu_device *adev = amdgpu_ttm_adev(vm->root.bo->tbo.bdev);
+		int major, minor;
+
+		amdgpu_vm_render_devt(adev, &major, &minor);
+
+		if (vm->task_info->task.pid)
+			trace_amdgpu_deregister_pid(vm->task_info->task.pid,
+						    major, minor);
+		trace_amdgpu_register_pid(current->pid, major, minor);
+	}
+
 	vm->task_info->task.pid = current->pid;
 	get_task_comm(vm->task_info->task.comm, current);
 
@@ -2876,6 +2895,13 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 			 ti->process_name, ti->task.pid, ti->task.comm, ti->tgid);
 	}
 
+	if (vm->task_info && vm->task_info->task.pid) {
+		int major, minor;
+
+		amdgpu_vm_render_devt(adev, &major, &minor);
+		trace_amdgpu_deregister_pid(vm->task_info->task.pid, major, minor);
+	}
+
 	amdgpu_vm_put_task_info(vm->task_info);
 }