linux-kernel - Re: [PATCH] drm/msm/adreno: Make adreno quirks not overwrite each other

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Date:   Thu, 29 Dec 2022 11:47:30 +0100
From:   Marijn Suijten <marijn.suijten@...ainline.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     linux-arm-msm@...r.kernel.org, andersson@...nel.org,
        agross@...nel.org, krzysztof.kozlowski@...aro.org,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>,
        Emma Anholt <emma@...olt.net>,
        Jordan Crouse <jordan@...micpenguin.net>,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/msm/adreno: Make adreno quirks not overwrite each
 other

On 2022-12-29 11:18:45, Konrad Dybcio wrote:
> So far the adreno quirks have all been assigned with an OR operator,
> which is problematic, because they were assigned consecutive integer
> values, which makes checking them with an AND operator kind of no bueno..
> 
> Switch to using BIT(n) so that only the quirks that the programmer chose
> are taken into account when evaluating info->quirks & ADRENO_QUIRK_...
> 
> Fixes: b5f103ab98c7 ("drm/msm: gpu: Add A5XX target support")
> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>

Nice catch!

Reviewed-by: Marijn Suijten <marijn.suijten@...ainline.org>

Not sure if it's the right Fixes commit though, as it would have worked
when ADRENO_QUIRK_LMLOADKILL_DISABLE was added with constant 4 instead
of 3 in 370063ee427a ("drm/msm/adreno: Add A540 support"), but then
using bitflags in an enum value type is invalid anyway, AFAIK.

- Marijn

> ---
>  drivers/gpu/drm/msm/adreno/adreno_gpu.h | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> index c85857c0a228..5eb254c9832a 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> @@ -29,11 +29,9 @@ enum {
>  	ADRENO_FW_MAX,
>  };
>  
> -enum adreno_quirks {
> -	ADRENO_QUIRK_TWO_PASS_USE_WFI = 1,
> -	ADRENO_QUIRK_FAULT_DETECT_MASK = 2,
> -	ADRENO_QUIRK_LMLOADKILL_DISABLE = 3,
> -};
> +#define ADRENO_QUIRK_TWO_PASS_USE_WFI		BIT(0)
> +#define ADRENO_QUIRK_FAULT_DETECT_MASK		BIT(1)
> +#define ADRENO_QUIRK_LMLOADKILL_DISABLE		BIT(2)
>  
>  struct adreno_rev {
>  	uint8_t  core;
> @@ -65,7 +63,7 @@ struct adreno_info {
>  	const char *name;
>  	const char *fw[ADRENO_FW_MAX];
>  	uint32_t gmem;
> -	enum adreno_quirks quirks;
> +	u64 quirks;
>  	struct msm_gpu *(*init)(struct drm_device *dev);
>  	const char *zapfw;
>  	u32 inactive_period;
> -- 
> 2.39.0
>