Re: [PATCH 2/2] drm/xe/guc: Add support for NPK as a GuC log target

["Summers, Stuart" <stuart.summers@intel.com>]

On Wed, 2025-06-11 at 14:05 -0700, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
> 
> The GuC has an option to write log data via NPK. This is basically a
> magic IO address that GuC writes arbitrary data to and which can be
> logged by a suitable hardware logger. This can allow retrieval of the
> GuC log in hardware debug environments even when the system as a
> whole
> dies horribly.
> 
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
>  drivers/gpu/drm/xe/xe_guc.c    | 4 ++++
>  drivers/gpu/drm/xe/xe_module.c | 4 ++++
>  drivers/gpu/drm/xe/xe_module.h | 1 +
>  3 files changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc.c
> b/drivers/gpu/drm/xe/xe_guc.c
> index e16d19b44bcc..9c0e3113f7d5 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -35,6 +35,7 @@
>  #include "xe_guc_submit.h"
>  #include "xe_memirq.h"
>  #include "xe_mmio.h"
> +#include "xe_module.h"
>  #include "xe_platform_types.h"
>  #include "xe_sriov.h"
>  #include "xe_uc.h"
> @@ -74,6 +75,9 @@ static u32 guc_ctl_debug_flags(struct xe_guc *guc)
>         else
>                 flags |= FIELD_PREP(GUC_LOG_VERBOSITY,
> GUC_LOG_LEVEL_TO_VERBOSITY(level));
>  
> +       if (xe_modparam.guc_log_target)
> +               flags |= FIELD_PREP(GUC_LOG_DESTINATION,
> xe_modparam.guc_log_target);

We do have the new configfs entries. Is there a reason to keep this in
the modparams instead of moving to configfs?

-Stuart

> +
>         return flags;
>  }
>  
> diff --git a/drivers/gpu/drm/xe/xe_module.c
> b/drivers/gpu/drm/xe/xe_module.c
> index 1c4dfafbcd0b..fc8c681819b9 100644
> --- a/drivers/gpu/drm/xe/xe_module.c
> +++ b/drivers/gpu/drm/xe/xe_module.c
> @@ -21,6 +21,7 @@
>  struct xe_modparam xe_modparam = {
>         .probe_display = true,
>         .guc_log_level = 3,
> +       .guc_log_target = 0,
>         .force_probe = CONFIG_DRM_XE_FORCE_PROBE,
>  #ifdef CONFIG_PCI_IOV
>         .max_vfs = IS_ENABLED(CONFIG_DRM_XE_DEBUG) ? ~0 : 0,
> @@ -45,6 +46,9 @@ MODULE_PARM_DESC(vram_bar_size, "Set the vram bar
> size (in MiB) - <0=disable-res
>  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..5=enable with verbosity min..max)");
>  
> +module_param_named(guc_log_target, xe_modparam.guc_log_target, int,
> 0600);
> +MODULE_PARM_DESC(guc_log_target, "GuC firmware logging target
> (0=memory [default], 1 = NPK, 2 = memory + NPK)");
> +
>  module_param_named_unsafe(guc_firmware_path,
> xe_modparam.guc_firmware_path, charp, 0400);
>  MODULE_PARM_DESC(guc_firmware_path,
>                  "GuC firmware path to use instead of the default
> one");
> diff --git a/drivers/gpu/drm/xe/xe_module.h
> b/drivers/gpu/drm/xe/xe_module.h
> index 5a3bfea8b7b4..4d978f6f26b6 100644
> --- a/drivers/gpu/drm/xe/xe_module.h
> +++ b/drivers/gpu/drm/xe/xe_module.h
> @@ -14,6 +14,7 @@ struct xe_modparam {
>         bool probe_display;
>         u32 force_vram_bar_size;
>         int guc_log_level;
> +       int guc_log_target;
>         char *guc_firmware_path;
>         char *huc_firmware_path;
>         char *gsc_firmware_path;