Re: [PATCH 8/8] drm/amd/display: copy function name into dcn_optc_lock_unlock_state trace event

[Tvrtko Ursulin <tvrtko.ursulin@igalia.com>]

On 24/09/2026 22:10, Melissa Wen wrote:
> Userspace trace tools that use libtraceevent to read binary buffer only
> see a kernel address when printing const char *. Use string macros in
> dcn_optc_lock_unlock_state to copy the function name into the trace
> event.
> 
> Fixes: f1943a51f0f9 ("drm/amd/display: Add events log to trace OPTC lock and unlock")
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Melissa Wen <mwen@igalia.com>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h
> index b2f38654e489..7f05f73e5b33 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_trace.h
> @@ -660,7 +660,7 @@ TRACE_EVENT(dcn_optc_lock_unlock_state,
>   	    TP_ARGS(optc_state, instance, lock, function, line),
>   
>   	    TP_STRUCT__entry(
> -			     __field(const char *, function)
> +			     __string(function, function)
>   			     __field(int, instance)
>   			     __field(bool, lock)
>   			     __field(int, line)
> @@ -678,7 +678,7 @@ TRACE_EVENT(dcn_optc_lock_unlock_state,
>   			     __field(int, vready_offset)
>   	    ),
>   	    TP_fast_assign(
> -			   __entry->function = function;
> +			   __assign_str(function);
>   			   __entry->instance = instance;
>   			   __entry->lock = lock;
>   			   __entry->line = line;
> @@ -700,7 +700,7 @@ TRACE_EVENT(dcn_optc_lock_unlock_state,
>   		      "min_v_blank_interlace=%d vstartup_start=%d vupdate_offset=%d vupdate_width=%d "
>   		      "vready_offset=%d",
>   		      __entry->lock ? "Lock" : "Unlock",
> -		      __entry->function,
> +		      __get_str(function),
>   		      __entry->line,
>   		      __entry->instance,
>   		      __entry->opp_count,

Hmm this one does have the macro->function->macro->function trick unlike 
the previous patch so unless I am wrong function name and line number 
are always the same? Ie. it could be converted to two separate 
tracepoints and would just lose the (questionable) line number.

Regards,

Tvrtko