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Message-ID: <2ce64f0a-8e31-4019-8d3e-49ca3ddd4766@quicinc.com>
Date:   Tue, 13 Sep 2022 16:01:19 -0700
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Subject: Re: [Freedreno] [PATCH] drm/msm: Fix return type of
 mdp4_lvds_connector_mode_valid
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To:     Nathan Huckleberry <nhuck@google.com>
CC:     <freedreno@lists.freedesktop.org>,
        Dan Carpenter <error27@gmail.com>,
        David Airlie <airlied@linux.ie>, Tom Rix <trix@redhat.com>,
        <llvm@lists.linux.dev>, Nick Desaulniers <ndesaulniers@google.com>,
        <dri-devel@lists.freedesktop.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Rob Clark <robdclark@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        <linux-arm-msm@vger.kernel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sean Paul <sean@poorly.run>, <linux-kernel@vger.kernel.org>
References: <20220913205551.155128-1-nhuck@google.com>
From:   Abhinav Kumar <quic_abhinavk@quicinc.com>
In-Reply-To: <20220913205551.155128-1-nhuck@google.com>
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Precedence: bulk

Hi Nathan

Thanks for the patch.

On 9/13/2022 1:55 PM, Nathan Huckleberry wrote:
> The mode_valid field in drm_connector_helper_funcs is expected to be of
> type:
> enum drm_mode_status (* mode_valid) (struct drm_connector *connector,
>                                       struct drm_display_mode *mode);
> 
> The mismatched return type breaks forward edge kCFI since the underlying
> function definition does not match the function hook definition.
> 
> The return type of mdp4_lvds_connector_mode_valid should be changed from
> int to enum drm_mode_status.
> 
> Reported-by: Dan Carpenter <error27@gmail.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Cc: llvm@lists.linux.dev
> Signed-off-by: Nathan Huckleberry <nhuck@google.com>

 From what I can see this one has been this way since lvds support was 
added. Hence this should have

Fixes: 3e87599b68e7 ("drm/msm/mdp4: add LVDS panel support")

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> ---
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
> index 7288041dd86a..7444b75c4215 100644
> --- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
> +++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_lvds_connector.c
> @@ -56,8 +56,9 @@ static int mdp4_lvds_connector_get_modes(struct drm_connector *connector)
>   	return ret;
>   }
>   
> -static int mdp4_lvds_connector_mode_valid(struct drm_connector *connector,
> -				 struct drm_display_mode *mode)
> +static enum drm_mode_status
> +mdp4_lvds_connector_mode_valid(struct drm_connector *connector,
> +			       struct drm_display_mode *mode)
>   {
>   	struct mdp4_lvds_connector *mdp4_lvds_connector =
>   			to_mdp4_lvds_connector(connector);