linux-kernel - Re: [PATCH RFT v2 07/15] drm/msm/a6xx: Resolve the meaning of UBWC

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Message-ID: <xzmvy6ulog67b5ibzg5gm37rvxerbwszoq3qr47kapj2rbjeuf@wr25nsuasa4d>
Date: Wed, 14 May 2025 22:14:56 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Konrad Dybcio <konradybcio@...nel.org>
Cc: Bjorn Andersson <andersson@...nel.org>, Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Subject: Re: [PATCH RFT v2 07/15] drm/msm/a6xx: Resolve the meaning of
 UBWC_MODE

On Wed, May 14, 2025 at 05:10:27PM +0200, Konrad Dybcio wrote:
> From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
> 
> This bit is set iff the UBWC version is 1.0. That notably does not
> include QCM2290's "no UBWC".
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
> ---
>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index e7c89f9c7d89798699848743843eed6a58b94bd3..6af4e70c1b936a30c1934dd49f2889be13c9780d 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -669,10 +669,10 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
>  	 */
>  	BUG_ON(adreno_gpu->ubwc_config.highest_bank_bit < 13);
>  	u32 hbb = adreno_gpu->ubwc_config.highest_bank_bit - 13;
> +	bool ubwc_mode = qcom_ubwc_get_ubwc_mode(cfg);

I'd really prefer if the function came in this patch rather than being
added at some earlier point. I understand that you want to simplify
cross-tree merging, but I think we should also simplify reviewing.

>  	bool amsbc = cfg->ubwc_enc_version >= UBWC_3_0;
>  	u32 hbb_hi = hbb >> 2;
>  	u32 hbb_lo = hbb & 3;
> -	u32 ubwc_mode = adreno_gpu->ubwc_config.ubwc_swizzle & 1;
>  	u32 level2_swizzling_dis = !(adreno_gpu->ubwc_config.ubwc_swizzle & 2);
>  
>  	gpu_write(gpu, REG_A6XX_RB_NC_MODE_CNTL,
> 
> -- 
> 2.49.0
> 

-- 
With best wishes
Dmitry