linux-kernel - Re: [PATCH 1/7] drm/msm/a5xx: Remove overwriting A5XX_PC_DBG_ECO

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Message-ID: <20200928162107.GC29832@jcrouse1-lnx.qualcomm.com>
Date:   Mon, 28 Sep 2020 10:21:08 -0600
From:   Jordan Crouse <jcrouse@...eaurora.org>
To:     kholk11@...il.com
Cc:     robdclark@...il.com, sean@...rly.run, airlied@...ux.ie,
        daniel@...ll.ch, konradybcio@...il.com, marijns95@...il.com,
        martin.botka1@...il.com, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, phone-devel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/7] drm/msm/a5xx: Remove overwriting
 A5XX_PC_DBG_ECO_CNTL register

On Sat, Sep 26, 2020 at 02:51:40PM +0200, kholk11@...il.com wrote:
> From: AngeloGioacchino Del Regno <kholk11@...il.com>
> 
> The PC_DBG_ECO_CNTL register on the Adreno A5xx family gets
> programmed to some different values on a per-model basis.
> At least, this is what we intend to do here;
> 
> Unfortunately, though, this register is being overwritten with a
> static magic number, right after applying the GPU-specific
> configuration (including the GPU-specific quirks) and that is
> effectively nullifying the efforts.
> 
> Let's remove the redundant and wrong write to the PC_DBG_ECO_CNTL
> register in order to retain the wanted configuration for the
> target GPU.

This was probably inherited from downstream which doesn't mind RMWing the same
register multiple times.


Reviewed-by: Jordan Crouse <jcrouse@...eaurora.org>

> Signed-off-by: AngeloGioacchino Del Regno <kholk11@...il.com>
> ---
>  drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> index 91726da82ed6..6262603e6e2e 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> @@ -594,8 +594,6 @@ static int a5xx_hw_init(struct msm_gpu *gpu)
>  	if (adreno_gpu->info->quirks & ADRENO_QUIRK_TWO_PASS_USE_WFI)
>  		gpu_rmw(gpu, REG_A5XX_PC_DBG_ECO_CNTL, 0, (1 << 8));
>  
> -	gpu_write(gpu, REG_A5XX_PC_DBG_ECO_CNTL, 0xc0200100);
> -
>  	/* Enable USE_RETENTION_FLOPS */
>  	gpu_write(gpu, REG_A5XX_CP_CHICKEN_DBG, 0x02000000);
>  
> -- 
> 2.28.0
> 

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