[PATCH] drm/bridge/synopsys: dw-hdmi: Fix unwedge crash when no pinctrl entries

[PATCH] drm/bridge/synopsys: dw-hdmi: Fix unwedge crash when no pinctrl entries

[Douglas Anderson]

In commit 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge"
for ddc bus") I stupidly used IS_ERR() to check for whether we have an
"unwedge" pinctrl state even though on most flows through the driver
the unwedge state will just be NULL.

Fix it so that we consistently use NULL for no unwedge state.

Fixes: 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus")
Reported-by: Erico Nunes <nunes.erico@gmail.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index f25e091b93c5..5e4e9408d00f 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -251,7 +251,7 @@ static void dw_hdmi_i2c_init(struct dw_hdmi *hdmi)
 static bool dw_hdmi_i2c_unwedge(struct dw_hdmi *hdmi)
 {
 	/* If no unwedge state then give up */
-	if (IS_ERR(hdmi->unwedge_state))
+	if (!hdmi->unwedge_state)
 		return false;
 
 	dev_info(hdmi->dev, "Attempting to unwedge stuck i2c bus\n");
@@ -2686,11 +2686,13 @@ __dw_hdmi_probe(struct platform_device *pdev,
 			hdmi->default_state =
 				pinctrl_lookup_state(hdmi->pinctrl, "default");
 
-			if (IS_ERR(hdmi->default_state) &&
-			    !IS_ERR(hdmi->unwedge_state)) {
-				dev_warn(dev,
-					 "Unwedge requires default pinctrl\n");
-				hdmi->unwedge_state = ERR_PTR(-ENODEV);
+			if (IS_ERR(hdmi->default_state) ||
+			    IS_ERR(hdmi->unwedge_state)) {
+				if (!IS_ERR(hdmi->unwedge_state))
+					dev_warn(dev,
+						 "Unwedge requires default pinctrl\n");
+				hdmi->default_state = NULL;
+				hdmi->unwedge_state = NULL;
 			}
 		}
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog

Re: [PATCH] drm/bridge/synopsys: dw-hdmi: Fix unwedge crash when no pinctrl entries

[Sean Paul]

On Mon, Jun 10, 2019 at 1:52 PM Douglas Anderson <dianders@chromium.org> wrote:
>
> In commit 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge"
> for ddc bus") I stupidly used IS_ERR() to check for whether we have an
> "unwedge" pinctrl state even though on most flows through the driver
> the unwedge state will just be NULL.
>
> Fix it so that we consistently use NULL for no unwedge state.
>
> Fixes: 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus")
> Reported-by: Erico Nunes <nunes.erico@gmail.com>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Thanks Erico for the report, and Doug for fixing this up quickly, I've applied
the patch to drm-misc-next

Sean

> ---
>
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index f25e091b93c5..5e4e9408d00f 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -251,7 +251,7 @@ static void dw_hdmi_i2c_init(struct dw_hdmi *hdmi)
>  static bool dw_hdmi_i2c_unwedge(struct dw_hdmi *hdmi)
>  {
>         /* If no unwedge state then give up */
> -       if (IS_ERR(hdmi->unwedge_state))
> +       if (!hdmi->unwedge_state)
>                 return false;
>
>         dev_info(hdmi->dev, "Attempting to unwedge stuck i2c bus\n");
> @@ -2686,11 +2686,13 @@ __dw_hdmi_probe(struct platform_device *pdev,
>                         hdmi->default_state =
>                                 pinctrl_lookup_state(hdmi->pinctrl, "default");
>
> -                       if (IS_ERR(hdmi->default_state) &&
> -                           !IS_ERR(hdmi->unwedge_state)) {
> -                               dev_warn(dev,
> -                                        "Unwedge requires default pinctrl\n");
> -                               hdmi->unwedge_state = ERR_PTR(-ENODEV);
> +                       if (IS_ERR(hdmi->default_state) ||
> +                           IS_ERR(hdmi->unwedge_state)) {
> +                               if (!IS_ERR(hdmi->unwedge_state))
> +                                       dev_warn(dev,
> +                                                "Unwedge requires default pinctrl\n");
> +                               hdmi->default_state = NULL;
> +                               hdmi->unwedge_state = NULL;
>                         }
>                 }
>
> --
> 2.22.0.rc2.383.gf4fbbf30c2-goog
>

Re: [PATCH] drm/bridge/synopsys: dw-hdmi: Fix unwedge crash when no pinctrl entries

[Erico Nunes]

On Mon, Jun 10, 2019 at 10:51 PM Sean Paul <sean@poorly.run> wrote:
>
> On Mon, Jun 10, 2019 at 1:52 PM Douglas Anderson <dianders@chromium.org> wrote:
> >
> > In commit 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge"
> > for ddc bus") I stupidly used IS_ERR() to check for whether we have an
> > "unwedge" pinctrl state even though on most flows through the driver
> > the unwedge state will just be NULL.
> >
> > Fix it so that we consistently use NULL for no unwedge state.
> >
> > Fixes: 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus")
> > Reported-by: Erico Nunes <nunes.erico@gmail.com>
> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
>
> Thanks Erico for the report, and Doug for fixing this up quickly, I've applied
> the patch to drm-misc-next

It does fix the issue. Thank you for the quick fix.

Erico