[Intel-gfx] [PATCH] drm/i915: Fix workarounds on Gen2-3

[Matt Roper]

On Fri, Nov 18, 2022 at 11:52:49AM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> In 3653727560d0 ("drm/i915: Simplify internal helper function signature")
> I broke the old platforms by not noticing engine workaround init does not
> initialize the list on old platforms. Fix it by always initializing which
> already does the right thing by mostly not doing anything if there aren't
> any workarounds on the list.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Fixes: 3653727560d0 ("drm/i915: Simplify internal helper function signature")
> Reported-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_workarounds.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> index 213160f29ec3..4d7a01b45e09 100644
> --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> @@ -2991,7 +2991,7 @@ general_render_compute_wa_init(struct intel_engine_cs *engine, struct i915_wa_li
>  static void
>  engine_init_workarounds(struct intel_engine_cs *engine, struct i915_wa_list *wal)
>  {
> -	if (I915_SELFTEST_ONLY(GRAPHICS_VER(engine->i915) < 4))
> +	if (GRAPHICS_VER(engine->i915) < 4)
>  		return;

Do we even need this early return at all?  As far as I can see, letting
this function run its course doesn't wind up having any effect or cause
any problems (you still wind up with an empty list).

Regardless,

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>

>  
>  	engine_fake_wa_init(engine, wal);
> @@ -3016,9 +3016,6 @@ void intel_engine_init_workarounds(struct intel_engine_cs *engine)
>  {
>  	struct i915_wa_list *wal = &engine->wa_list;
>  
> -	if (GRAPHICS_VER(engine->i915) < 4)
> -		return;
> -
>  	wa_init_start(wal, engine->gt, "engine", engine->name);
>  	engine_init_workarounds(engine, wal);
>  	wa_init_finish(wal);
> -- 
> 2.34.1
> 

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation