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.

#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)

 #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)
 {