Re: [PATCH v2 3/3] drm/xe: Normalize default param values

[John Harrison <john.c.harrison@intel.com>]

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On 6/16/2025 11:52 AM, Lucas De Marchi wrote:
> On Mon, Jun 16, 2025 at 11:46:57AM -0700, John Harrison wrote:
>> On 6/13/2025 1:00 PM, Lucas De Marchi wrote:
>>> Document xe module params with the default values following a similar
>>> strategy for all of them:
>>>
>>>     1) Define a DEFAULT_* macro with the default value. When the
>>>        value can't be directly stringified, also define a *_STR
>>>        variant
>>>     2) Use __stringify() or the _STR variant to make sure the
>>>        default value shows up in the param description
>>>
>>> This allows us to show the correct default according to the
>>> configuration. max_vfs for example was wrongly documented for
>>> CONFIG_DRM_XE_DEBUG and svm_notifier_size didn't have its default
>>> documented.
>>>
>>> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
>>> ---
>>>  drivers/gpu/drm/xe/xe_module.c | 44 
>>> +++++++++++++++++++++++++++---------------
>>>  1 file changed, 28 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/xe/xe_module.c 
>>> b/drivers/gpu/drm/xe/xe_module.c
>>> index 192908fa074cb..2068c579d5c3b 100644
>>> --- a/drivers/gpu/drm/xe/xe_module.c
>>> +++ b/drivers/gpu/drm/xe/xe_module.c
>>> @@ -19,34 +19,43 @@
>>>  #include "xe_sched_job.h"
>>>  #if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
>>> -#define DEFAULT_GUC_LOG_LEVEL    3
>>> +#define DEFAULT_GUC_LOG_LEVEL        3
>>> +#define DEFAULT_MAX_VFS            ~0
>>> +#define DEFAULT_MAX_VFS_STR        "unlimited"
>>>  #else
>>> -#define DEFAULT_GUC_LOG_LEVEL    1
>>> +#define DEFAULT_GUC_LOG_LEVEL        1
>>> +#define DEFAULT_MAX_VFS            0
>>> +#define DEFAULT_MAX_VFS_STR        "0"
>> Could be 'stringify(MAX_VFS)'.
>
> I think it's better to pair with the one above.
> We don't want to print the the default is ~0 in the other case so we
> create a manual _STR.

I meant:

    #define DEFAULT_MAX_VFS            ~0
    #define DEFAULT_MAX_VFS_STR        "unlimited"
    #else
    #define DEFAULT_MAX_VFS            0
    #define DEFAULT_MAX_VFS_STR        __stringify(DEFAULT_MAX_VFS)


John.

>
>
>>
>>>  #endif
>>> +#define DEFAULT_PROBE_DISPLAY        true
>>> +#define DEFAULT_FORCE_PROBE        CONFIG_DRM_XE_FORCE_PROBE
>>> +#define DEFAULT_WEDGED_MODE        1
>>> +#define DEFAULT_SVM_NOTIFIER_SIZE    512
>>> +
>>>  struct xe_modparam xe_modparam = {
>>> -    .probe_display = true,
>>> -    .guc_log_level = DEFAULT_GUC_LOG_LEVEL,
>>> -    .force_probe = CONFIG_DRM_XE_FORCE_PROBE,
>>> -#ifdef CONFIG_PCI_IOV
>> This ifdef is lost from the new version?
>
> yeah, dropped it by mistake... will need to add it back.
>>
>>> -    .max_vfs = IS_ENABLED(CONFIG_DRM_XE_DEBUG) ? ~0 : 0,
>>> -#endif
>>> -    .wedged_mode = 1,
>>> -    .svm_notifier_size = 512,
>>> +    .probe_display =    DEFAULT_PROBE_DISPLAY,
>>> +    .guc_log_level =    DEFAULT_GUC_LOG_LEVEL,
>>> +    .force_probe =        DEFAULT_FORCE_PROBE,
>>> +    .max_vfs =        DEFAULT_MAX_VFS,
>>> +    .wedged_mode =        DEFAULT_WEDGED_MODE,
>>> +    .svm_notifier_size =    DEFAULT_SVM_NOTIFIER_SIZE,
>>>      /* the rest are 0 by default */
>>>  };
>>>  module_param_named(svm_notifier_size, 
>>> xe_modparam.svm_notifier_size, uint, 0600);
>>> -MODULE_PARM_DESC(svm_notifier_size, "Set the svm notifier size(in 
>>> MiB), must be power of 2");
>>> +MODULE_PARM_DESC(svm_notifier_size, "Set the svm notifier size in 
>>> MiB, must be power of 2 "
>>> +         "[default=" __stringify(DEFAULT_SVM_NOTIFIER_SIZE) "]");
>>>  module_param_named_unsafe(force_execlist, 
>>> xe_modparam.force_execlist, bool, 0444);
>>>  MODULE_PARM_DESC(force_execlist, "Force Execlist submission");
>>>  module_param_named(probe_display, xe_modparam.probe_display, bool, 
>>> 0444);
>>> -MODULE_PARM_DESC(probe_display, "Probe display HW, otherwise it's 
>>> left untouched (default: true)");
>>> +MODULE_PARM_DESC(probe_display, "Probe display HW, otherwise it's 
>>> left untouched "
>>> +         "[default=" __stringify(DEFAULT_PROBE_DISPLAY) "])");
>>>  module_param_named(vram_bar_size, xe_modparam.force_vram_bar_size, 
>>> int, 0600);
>>> -MODULE_PARM_DESC(vram_bar_size, "Set the vram bar size (in MiB) - 
>>> <0=disable-resize, 0=max-needed-size[default], >0=force-size");
>>> +MODULE_PARM_DESC(vram_bar_size, "Set the vram bar size in MiB 
>>> (<0=disable-resize, 0=max-needed-size, >0=force-size [default=0])");
>> Why leave this one as hard coded value rather than a define?
>
> there wasn't an assignment xe_modparam, so I overlooked it. I will fix
> those up in next rev
>
> thanks
> Lucas De Marchi
>
>
>>
>> John.
>>
>>>  module_param_named(guc_log_level, xe_modparam.guc_log_level, int, 
>>> 0600);
>>>  MODULE_PARM_DESC(guc_log_level, "GuC firmware logging level 
>>> (0=disable, 1=normal, 2..5=verbose-levels "
>>> @@ -66,18 +75,21 @@ MODULE_PARM_DESC(gsc_firmware_path,
>>>  module_param_named_unsafe(force_probe, xe_modparam.force_probe, 
>>> charp, 0400);
>>>  MODULE_PARM_DESC(force_probe,
>>> -         "Force probe options for specified devices. See 
>>> CONFIG_DRM_XE_FORCE_PROBE for details.");
>>> +         "Force probe options for specified devices. See 
>>> CONFIG_DRM_XE_FORCE_PROBE for details "
>>> +         "[default=" DEFAULT_FORCE_PROBE "])");
>>>  #ifdef CONFIG_PCI_IOV
>>>  module_param_named(max_vfs, xe_modparam.max_vfs, uint, 0400);
>>>  MODULE_PARM_DESC(max_vfs,
>>>           "Limit number of Virtual Functions (VFs) that could be 
>>> managed. "
>>> -         "(0 = no VFs [default]; N = allow up to N VFs)");
>>> +         "(0=no VFs; N=allow up to N VFs "
>>> +         "[default=" DEFAULT_MAX_VFS_STR "])");
>>>  #endif
>>>  module_param_named_unsafe(wedged_mode, xe_modparam.wedged_mode, 
>>> int, 0600);
>>>  MODULE_PARM_DESC(wedged_mode,
>>> -         "Module's default policy for the wedged mode - 0=never, 
>>> 1=upon-critical-errors[default], 2=upon-any-hang");
>>> +         "Module's default policy for the wedged mode (0=never, 
>>> 1=upon-critical-errors, 2=upon-any-hang "
>>> +         "[default=" __stringify(DEFAULT_WEDGED_MODE) "])");
>>>  static int xe_check_nomodeset(void)
>>>  {
>>>
>>

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