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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Sat, 8 May 2021 03:58:12 -0400
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Subject: Re: [PATCH 1/1] drm/msm/dpu: Fix error return code in dpu_mdss_init()
To:     Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
        Leizhen <thunder.leizhen@huawei.com>,
        Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        freedreno <freedreno@lists.freedesktop.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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Precedence: bulk

Quoting Leizhen (ThunderTown) (2021-05-08 00:55:04)
>
>
> On 2021/5/8 14:09, Stephen Boyd wrote:
> > Quoting Zhen Lei (2021-05-07 19:42:54)
> >> Fix to return a negative error code from the error handling case instead
> >> of 0, as done elsewhere in this function.
> >>
> >> Fixes: 070e64dc1bbc ("drm/msm/dpu: Convert to a chained irq chip")
> >> Reported-by: Hulk Robot <hulkci@huawei.com>
> >> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> >> ---
> >>  drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> >> index 06b56fec04e0..1b6c9fb500a1 100644
> >> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> >> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> >> @@ -253,8 +253,10 @@ int dpu_mdss_init(struct drm_device *dev)
> >>                 goto irq_domain_error;
> >>
> >>         irq = platform_get_irq(pdev, 0);
> >> -       if (irq < 0)
> >> +       if (irq < 0) {
> >> +               ret = irq;
> >>                 goto irq_error;
> >> +       }
> >
> > It would be even better if ret wasn't assigned to 0 at the start of this
> > function.
>
> The returned error code is not unique.
>

What does it mean? I was saying this

----8<----
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
index cd4078807db1..0fcf190f6322 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
@@ -263,7 +263,7 @@ int dpu_mdss_init(struct drm_device *dev)
 	struct msm_drm_private *priv = dev->dev_private;
 	struct dpu_mdss *dpu_mdss;
 	struct dss_module_power *mp;
-	int ret = 0;
+	int ret;
 	int irq;

 	dpu_mdss = devm_kzalloc(dev->dev, sizeof(*dpu_mdss), GFP_KERNEL);
@@ -297,8 +297,10 @@ int dpu_mdss_init(struct drm_device *dev)
 		goto irq_domain_error;

 	irq = platform_get_irq(pdev, 0);
-	if (irq < 0)
+	if (irq < 0) {
+		ret = irq;
 		goto irq_error;
+	}

 	irq_set_chained_handler_and_data(irq, dpu_mdss_irq,
 					 dpu_mdss);
@@ -309,7 +311,7 @@ int dpu_mdss_init(struct drm_device *dev)

 	dpu_mdss_icc_request_bw(priv->mdss);

-	return ret;
+	return 0;

 irq_error:
 	_dpu_mdss_irq_domain_fini(dpu_mdss);