[PATCH] drm/gma500: fix a missing break in psb_driver_load

[PATCH] drm/gma500: fix a missing break in psb_driver_load

[Xiaomeng Tong]

Instead of exiting the loop as expected when an entry is found, the
list_for_each_entry() continues until the traversal is complete. To
avoid potential executing 'ret = gma_backlight_init(dev);' repeatly,
break the loop when the entry is found.

Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---
 drivers/gpu/drm/gma500/psb_drv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c
index 2aff54d505e2..b61a8b0eea38 100644
--- a/drivers/gpu/drm/gma500/psb_drv.c
+++ b/drivers/gpu/drm/gma500/psb_drv.c
@@ -402,6 +402,9 @@ static int psb_driver_load(struct drm_device *dev, unsigned long flags)
 			ret = gma_backlight_init(dev);
 			break;
 		}
+
+		if (!ret)
+			break;
 	}
 	drm_connector_list_iter_end(&conn_iter);
 
-- 
2.17.1

Re: [PATCH] drm/gma500: fix a missing break in psb_driver_load

[Patrik Jakobsson]

On Fri, Apr 1, 2022 at 1:58 PM Xiaomeng Tong <xiam0nd.tong@gmail.com> wrote:
>
> Instead of exiting the loop as expected when an entry is found, the
> list_for_each_entry() continues until the traversal is complete. To
> avoid potential executing 'ret = gma_backlight_init(dev);' repeatly,
> break the loop when the entry is found.
>
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
> ---
>  drivers/gpu/drm/gma500/psb_drv.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c
> index 2aff54d505e2..b61a8b0eea38 100644
> --- a/drivers/gpu/drm/gma500/psb_drv.c
> +++ b/drivers/gpu/drm/gma500/psb_drv.c
> @@ -402,6 +402,9 @@ static int psb_driver_load(struct drm_device *dev, unsigned long flags)
>                         ret = gma_backlight_init(dev);
>                         break;
>                 }
> +
> +               if (!ret)
> +                       break;

Hi,
We cannot do it like this either. If the first connector isn't LVDS or
MIPI we would just break out of the iteration because ret is
presumably 0 at start and gma_backlight_init() would never run.

-Patrik

>         }
>         drm_connector_list_iter_end(&conn_iter);
>
> --
> 2.17.1
>

Re: [PATCH] drm/gma500: fix a missing break in psb_driver_load

[Xiaomeng Tong]

On Wed, 6 Apr 2022 09:27:19 +0200, Patrik Jakobsson wrote:
> On Fri, Apr 1, 2022 at 1:58 PM Xiaomeng Tong <xiam0nd.tong@gmail.com> wrote:
> >
> > Instead of exiting the loop as expected when an entry is found, the
> > list_for_each_entry() continues until the traversal is complete. To
> > avoid potential executing 'ret = gma_backlight_init(dev);' repeatly,
> > break the loop when the entry is found.
> >
> > Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
> > ---
> >  drivers/gpu/drm/gma500/psb_drv.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c
> > index 2aff54d505e2..b61a8b0eea38 100644
> > --- a/drivers/gpu/drm/gma500/psb_drv.c
> > +++ b/drivers/gpu/drm/gma500/psb_drv.c
> > @@ -402,6 +402,9 @@ static int psb_driver_load(struct drm_device *dev, unsigned long flags)
> >                         ret = gma_backlight_init(dev);
> >                         break;
> >                 }
> > +
> > +               if (!ret)
> > +                       break;
> 
> Hi,
> We cannot do it like this either. If the first connector isn't LVDS or
> MIPI we would just break out of the iteration because ret is
> presumably 0 at start and gma_backlight_init() would never run.
> 
> -Patrik

Yes, you are correct. I have sent a v2 patch[1]: just goto out; when found.
Please check it, thank you very much.

[1]: https://lore.kernel.org/all/20220406113143.10699-1-xiam0nd.tong@gmail.com/

--
Xiaomeng Tong
 
> 
> >         }
> >         drm_connector_list_iter_end(&conn_iter);
> >
> > --
> > 2.17.1