Re: [PATCH v2] drm/xe/guc: Update GuC log buffer type value

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 9/4/2025 5:14 PM, Zhanjun Dong wrote:
> Update GuC log buffer type value, to align with the GuC specification.
> 
> Signed-off-by: Zhanjun Dong <zhanjun.dong@intel.com>
> ---
> Change list:
> v2: Use SZ_4K, instead of PAGE_SIZE
>     Expand for loop with switch and fallthrough
> ---
>  drivers/gpu/drm/xe/abi/guc_log_abi.h |  2 +-
>  drivers/gpu/drm/xe/xe_guc_log.c      | 20 ++++++++++++--------
>  2 files changed, 13 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/abi/guc_log_abi.h b/drivers/gpu/drm/xe/abi/guc_log_abi.h
> index 554630b7ccd9..b1819679fa35 100644
> --- a/drivers/gpu/drm/xe/abi/guc_log_abi.h
> +++ b/drivers/gpu/drm/xe/abi/guc_log_abi.h
> @@ -10,8 +10,8 @@
>  
>  /* GuC logging buffer types */
>  enum guc_log_buffer_type {
> -	GUC_LOG_BUFFER_CRASH_DUMP,
>  	GUC_LOG_BUFFER_DEBUG,
> +	GUC_LOG_BUFFER_CRASH_DUMP,
>  	GUC_LOG_BUFFER_CAPTURE,
>  };
>  
> diff --git a/drivers/gpu/drm/xe/xe_guc_log.c b/drivers/gpu/drm/xe/xe_guc_log.c
> index c01ccb35dc75..6cbb0378d2ba 100644
> --- a/drivers/gpu/drm/xe/xe_guc_log.c
> +++ b/drivers/gpu/drm/xe/xe_guc_log.c
> @@ -50,7 +50,7 @@ static size_t guc_log_size(void)
>  	 *  |     Capture state header      |
>  	 *  +-------------------------------+ 96B
>  	 *  |                               |
> -	 *  +===============================+ PAGE_SIZE (4KB)
> +	 *  +===============================+ 4KB
>  	 *  |        Crash Dump logs        |
>  	 *  +===============================+ + CRASH_SIZE
>  	 *  |          Debug logs           |
> @@ -58,7 +58,7 @@ static size_t guc_log_size(void)
>  	 *  |         Capture logs          |
>  	 *  +===============================+ + CAPTURE_SIZE
>  	 */
> -	return PAGE_SIZE + CRASH_BUFFER_SIZE + DEBUG_BUFFER_SIZE +
> +	return SZ_4K + CRASH_BUFFER_SIZE + DEBUG_BUFFER_SIZE +
>  		CAPTURE_BUFFER_SIZE;

nit: can you do the math in the same order as on diagram?

	return 4K + DEBUG + CRASH + CAPTURE

and btw, since in this function you are using hardcoded values

>  }
>  
> @@ -327,13 +327,17 @@ u32 xe_guc_get_log_buffer_size(struct xe_guc_log *log, enum guc_log_buffer_type
>   */
>  u32 xe_guc_get_log_buffer_offset(struct xe_guc_log *log, enum guc_log_buffer_type type)
>  {
> -	enum guc_log_buffer_type i;
> -	u32 offset = PAGE_SIZE;/* for the log_buffer_states */
> +	u32 offset = SZ_4K; /* 1st section size */
>  
> -	for (i = GUC_LOG_BUFFER_CRASH_DUMP; i < GUC_LOG_BUFFER_TYPE_MAX; ++i) {
> -		if (i == type)
> -			break;
> -		offset += xe_guc_get_log_buffer_size(log, i);
> +	switch (type) {
> +	case GUC_LOG_BUFFER_CAPTURE:
> +		offset += xe_guc_get_log_buffer_size(log, GUC_LOG_BUFFER_CRASH_DUMP);

do we need to use fancy helpers to finally get the same hardcoded value?

here it is just CRASH_BUFFER_SIZE

> +		fallthrough;
> +	case GUC_LOG_BUFFER_CRASH_DUMP:
> +		offset += xe_guc_get_log_buffer_size(log, GUC_LOG_BUFFER_DEBUG);

and here DEBUG_BUFFER_SIZE 

> +		fallthrough;
> +	case GUC_LOG_BUFFER_DEBUG:
> +		break;
>  	}
>  
>  	return offset;

then since XXX_BUFFER_SIZE macros are already in .h maybe we get kill those helpers?

and btw, those BUFFER_SIZE macros in .h should have likely have XE_GUC_LOG prefix
(since those are Xe driver specific) - something for next (or prerequisite patch)