Re: [PATCH v2 08/10] drm/xe/xe_late_bind_fw: Introduce debug fs node to disable late binding

[Daniele Ceraolo Spurio]

On 6/6/2025 10:57 AM, Badal Nilawar wrote:
Introduce a debug filesystem node to disable late binding fw reload
during the system or runtime resume. This is intended for situations
where the late binding fw needs to be loaded from user mode.

Can you clarify a bit what the use-case here is? Because this 
description makes it sound like this is something a user might want to 
do, but the debugfs interface is for testing only. If we only need this 
for testing, please specify so.


Signed-off-by: Badal Nilawar <badal.nila...@intel.com>
---
  drivers/gpu/drm/xe/xe_debugfs.c            | 42 ++++++++++++++++++++++
  drivers/gpu/drm/xe/xe_late_bind_fw.c       |  5 ++-
  drivers/gpu/drm/xe/xe_late_bind_fw_types.h |  3 ++
  3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
index d83cd6ed3fa8..1c145089d177 100644
--- a/drivers/gpu/drm/xe/xe_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_debugfs.c
@@ -226,6 +226,45 @@ static const struct file_operations 
atomic_svm_timeslice_ms_fops = {
        .write = atomic_svm_timeslice_ms_set,
  };
  
+static ssize_t disable_late_binding_show(struct file *f, char __user *ubuf,
+                                        size_t size, loff_t *pos)
+{
+       struct xe_device *xe = file_inode(f)->i_private;
+       struct xe_late_bind *late_bind = &xe->late_bind;
+       char buf[32];
+       int len;
+
+       len = scnprintf(buf, sizeof(buf), "%d\n", late_bind->disable);
+
+       return simple_read_from_buffer(ubuf, size, pos, buf, len);
+}
+
+static ssize_t disable_late_binding_set(struct file *f, const char __user 
*ubuf,
+                                       size_t size, loff_t *pos)
+{
+       struct xe_device *xe = file_inode(f)->i_private;
+       struct xe_late_bind *late_bind = &xe->late_bind;
+       u32 uval;
+       ssize_t ret;
+
+       ret = kstrtouint_from_user(ubuf, size, sizeof(uval), &uval);
+       if (ret)
+               return ret;
+
+       if (uval > 1)
+               return -EINVAL;
+
+       late_bind->disable = (uval == 1) ? true : false;

nit: could do

late_bind->disable = !!uval;

+
+       return size;
+}
+
+static const struct file_operations disable_late_binding_fops = {
+       .owner = THIS_MODULE,
+       .read = disable_late_binding_show,
+       .write = disable_late_binding_set,
+};
+
  void xe_debugfs_register(struct xe_device *xe)
  {
        struct ttm_device *bdev = &xe->ttm;
@@ -249,6 +288,9 @@ void xe_debugfs_register(struct xe_device *xe)
        debugfs_create_file("atomic_svm_timeslice_ms", 0600, root, xe,
                            &atomic_svm_timeslice_ms_fops);
  
+	debugfs_create_file("disable_late_binding", 0600, root, xe,
+                           &disable_late_binding_fops);
+
        for (mem_type = XE_PL_VRAM0; mem_type <= XE_PL_VRAM1; ++mem_type) {
                man = ttm_manager_type(bdev, mem_type);
  
diff --git a/drivers/gpu/drm/xe/xe_late_bind_fw.c b/drivers/gpu/drm/xe/xe_late_bind_fw.c
index d69f950bddd2..f9d3d0f341f2 100644
--- a/drivers/gpu/drm/xe/xe_late_bind_fw.c
+++ b/drivers/gpu/drm/xe/xe_late_bind_fw.c
@@ -123,11 +123,14 @@ int xe_late_bind_fw_load(struct xe_late_bind *late_bind)
        if (!late_bind->component_added)
                return -EINVAL;
  
+	if (late_bind->disable)
+               return 0;
+
        lbfw = &late_bind->late_bind_fw;
        if (lbfw->valid) {
                drm_dbg(&xe->drm, "Queue work: to load %s firmware\n",
                        fw_type_to_name[lbfw->type]);
-                       queue_work(late_bind->wq, &lbfw->work);
+               queue_work(late_bind->wq, &lbfw->work);

This seems to be a fix for a broken indent in a previous patch in the 
series, so it should be moved to that patch.

Daniele

        }
  
  	return 0;
diff --git a/drivers/gpu/drm/xe/xe_late_bind_fw_types.h 
b/drivers/gpu/drm/xe/xe_late_bind_fw_types.h
index 690680e8ff22..6f4a945ca236 100644
--- a/drivers/gpu/drm/xe/xe_late_bind_fw_types.h
+++ b/drivers/gpu/drm/xe/xe_late_bind_fw_types.h
@@ -76,6 +76,9 @@ struct xe_late_bind {
        struct xe_late_bind_fw late_bind_fw;
        /** @late_bind.wq: workqueue to submit request to download late bind 
blob */
        struct workqueue_struct *wq;
+
+       /** @late_bind.disable to block late binding reload during pm resume 
flow*/
+       bool disable;
  };
  
  #endif