[PATCH 08/10] drm/etnaviv: make it possible to reconfigure perf counter

[Wladimir J. van der Laan]

On Fri, Dec 09, 2016 at 12:21:29PM +0100, Christian Gmeiner wrote:
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> @@ -1379,6 +1379,9 @@ static void etnaviv_process_readbacks(struct etnaviv_gpu *gpu,
>  		const u32 val = gpu_read(gpu, readback->reg);
>  		u32 *bo = readback->bo_vma;
>  
> +		if (readback->flags & ETNA_READBACK_PERF)
> +			gpu_write(gpu, readback->perf_reg, readback->perf_value);
> +
>  		*(bo + readback->offset) = val;
>  	}
>  }

This is the wrong order. First write the selection register, then read the
counter. Currently this causes the reported registers to be off by one,
if they're read in sequential order.

Wladimir