Re: [PATCH v5 08/10] drm/xe/xe_late_bind_fw: Introduce debug fs node to disable late binding

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

On 7/2/2025 9:52 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,
> perticularly for validation purpose.
> Note that xe kmd doesn't participate in late binding flow from user
> space. Binary loaded from the userspace will be lost upon entering to
> D3 cold hence user space app need to handle this situation.
>
> v2:
>    - s/(uval == 1) ? true : false/!!uval/ (Daniele)
> v3:
>    - Refine the commit message (Daniele)
>
> Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> ---
>   drivers/gpu/drm/xe/xe_debugfs.c            | 41 ++++++++++++++++++++++
>   drivers/gpu/drm/xe/xe_late_bind_fw.c       |  3 ++
>   drivers/gpu/drm/xe/xe_late_bind_fw_types.h |  2 ++
>   3 files changed, 46 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
> index d83cd6ed3fa8..d1f6f556efa2 100644
> --- a/drivers/gpu/drm/xe/xe_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_debugfs.c
> @@ -226,6 +226,44 @@ 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;
> +	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 +287,9 @@ 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 3fb84d2f0a76..f6acf535bebc 100644
> --- a/drivers/gpu/drm/xe/xe_late_bind_fw.c
> +++ b/drivers/gpu/drm/xe/xe_late_bind_fw.c
> @@ -158,6 +158,9 @@ int xe_late_bind_fw_load(struct xe_late_bind *late_bind)
>   	if (!late_bind->component_added)
>   		return -ENODEV;
>   
> +	if (late_bind->disable)
> +		return 0;
> +
>   	for (fw_id = 0; fw_id < XE_LB_FW_MAX_ID; fw_id++) {
>   		lbfw = &late_bind->late_bind_fw[fw_id];
>   		if (lbfw->payload) {
> 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 0ed98f236f2a..9a7fd07bf122 100644
> --- a/drivers/gpu/drm/xe/xe_late_bind_fw_types.h
> +++ b/drivers/gpu/drm/xe/xe_late_bind_fw_types.h
> @@ -67,6 +67,8 @@ struct xe_late_bind {
>   	struct workqueue_struct *wq;
>   	/** @late_bind.component_added: whether the component has been added */
>   	bool component_added;
> +	/** @late_bind.disable to block late binding reload during pm resume flow*/
> +	bool disable;
>   };
>   
>   #endif