linux-kernel - Re: [PATCH v3 1/8] drm/msm/dp: fix HPD state status bit shift value

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Message-ID: <63065e3d-70bf-4178-bd92-04c6ba1a1340@oss.qualcomm.com>
Date: Thu, 15 Jan 2026 10:12:16 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        Rob Clark <robin.clark@....qualcomm.com>,
        Dmitry Baryshkov
 <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jesszhan0024@...il.com>, Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Jessica Zhang <jessica.zhang@....qualcomm.com>
Subject: Re: [PATCH v3 1/8] drm/msm/dp: fix HPD state status bit shift value

On 1/15/26 8:29 AM, Dmitry Baryshkov wrote:
> From: Jessica Zhang <jessica.zhang@....qualcomm.com>
> 
> The HPD state status is the 3 most significant bits, not 4 bits of the
> HPD_INT_STATUS register.

/me stares

BIT(28) is indeed not defined, at least on Hamoa.. Amazing luck things
worked..

> 
> Fix the bit shift macro so that the correct bits are returned in
> msm_dp_aux_is_link_connected().
> 
> Fixes: 19e52bcb27c2 ("drm/msm/dp: return correct connection status after suspend")
> Signed-off-by: Jessica Zhang <jessica.zhang@....qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_reg.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_reg.h b/drivers/gpu/drm/msm/dp/dp_reg.h
> index 7c44d4e2cf13..3689642b7fc0 100644
> --- a/drivers/gpu/drm/msm/dp/dp_reg.h
> +++ b/drivers/gpu/drm/msm/dp/dp_reg.h
> @@ -68,8 +68,8 @@
>  #define DP_DP_IRQ_HPD_INT_ACK			(0x00000002)
>  #define DP_DP_HPD_REPLUG_INT_ACK		(0x00000004)
>  #define DP_DP_HPD_UNPLUG_INT_ACK		(0x00000008)
> -#define DP_DP_HPD_STATE_STATUS_BITS_MASK	(0x0000000F)
> -#define DP_DP_HPD_STATE_STATUS_BITS_SHIFT	(0x1C)
> +#define DP_DP_HPD_STATE_STATUS_BITS_MASK	(0x00000007)
> +#define DP_DP_HPD_STATE_STATUS_BITS_SHIFT	(0x1D)

This file could use some genmasking..

Reviewed-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>

Konrad