[Intel-gfx] [PATCH] drm/i915/gt: Remove assignment from if condition

[Andi Shyti]

Hi Gilbert,

> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index e8f42ec6b1b4..cbc4ecf26d8b 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -1751,7 +1751,7 @@ static bool gen8_csb_parse(const u64 csb)
>  static noinline u64
>  wa_csb_read(const struct intel_engine_cs *engine, u64 * const csb)
>  {
> -	u64 entry;
> +	u64 entry = READ_ONCE(*csb);
>  
>  	/*
>  	 * Reading from the HWSP has one particular advantage: we can detect
> @@ -1763,7 +1763,7 @@ wa_csb_read(const struct intel_engine_cs *engine, u64 * const csb)
>  	 * tgl,dg1:HSDES#22011327657
>  	 */
>  	preempt_disable();
> -	if (wait_for_atomic_us((entry = READ_ONCE(*csb)) != -1, 10)) {
> +	if (wait_for_atomic_us(entry != -1, 10)) {

this doesn't work. Hav you looked inside the wait_for_atomic_us?
It's busy looping for 10us waiting for *csb to be different from
-1. Because the entry value won't have a chance to change, then
we would be waiting 10us for nothing.

Not all the checkpatch errors need to be fixed and we can live
with this one.

Andi

>  		int idx = csb - engine->execlists.csb_status;
>  		int status;
>  
> -- 
> 2.34.1