Re: [PATCH 8/9] drm/xe/xe_late_bind_fw: Introduce debug fs node to disable late binding

["Nilawar, Badal" <badal.nilawar@intel.com>]

On 01-08-2025 20:47, Rodrigo Vivi wrote:
> On Thu, Jul 31, 2025 at 08:03:36PM +0000, Summers, Stuart wrote:
>> On Thu, 2025-07-10 at 11:08 -0400, Rodrigo Vivi wrote:
>>> From: Badal Nilawar <badal.nilawar@intel.com>
>>>
>>> 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>
>>> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Bit of a flyby comment here, but would it be better if this was
>> configfs rather than debugfs in case we wanted to skip this on the
>> first probe?
> Indeed. Configfs seems the best alternative for this. Otherwise
> by the time we get to have the debugfs, the fw was already
> attempted to get loaded at least once.

Don't want to skip fw load during probe, that's why used debugfs.

Regards,
Badal

>
>> Thanks,
>> Stuart
>>
>>> ---
>>>   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 df43523e9043..88355adce1d0 100644
>>> --- a/drivers/gpu/drm/xe/xe_late_bind_fw.c
>>> +++ b/drivers/gpu/drm/xe/xe_late_bind_fw.c
>>> @@ -167,6 +167,9 @@ 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 5c0574aff7b9..158dc1abe072 100644
>>> --- a/drivers/gpu/drm/xe/xe_late_bind_fw_types.h
>>> +++ b/drivers/gpu/drm/xe/xe_late_bind_fw_types.h
>>> @@ -65,6 +65,8 @@ struct xe_late_bind {
>>>          struct workqueue_struct *wq;
>>>          /** @component_added: whether the component has been added */
>>>          bool component_added;
>>> +       /** @disable: to block late binding reload during pm resume
>>> flow*/
>>> +       bool disable;
>>>   };
>>>   
>>>   #endif