Re: [PATCH] drm/panel: atna33xc20: Fix unbalanced regulator in the case HPD doesn't assert

[Jessica Zhang]

On 3/13/2024 2:12 PM, Douglas Anderson via B4 Relay wrote:

From: Douglas Anderson <diand...@chromium.org>

When the atna33xc20 driver was first written the resume code never
returned an error. If there was a problem waiting for HPD it just
printed a warning and moved on. This changed in response to review
feedback [1] on a future patch but I accidentally didn't account for
rolling back the regulator enable in the error cases. Do so now.

[1] https://lore.kernel.org/all/5f3cf3a6-1cc2-63e4-f76b-4ee686764...@linaro.org/

Fixes: 3b5765df375c ("drm/panel: atna33xc20: Take advantage of wait_hpd_asserted() 
in struct drm_dp_aux")
Signed-off-by: Douglas Anderson <diand...@chromium.org>
---
  drivers/gpu/drm/panel/panel-samsung-atna33xc20.c | 22 +++++++++++++---------
  1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c 
b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
index 76c2a8f6718c..9c336c71562b 100644
--- a/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
+++ b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
@@ -109,19 +109,17 @@ static int atana33xc20_resume(struct device *dev)
                if (hpd_asserted < 0)
                        ret = hpd_asserted;

- if (ret)

+               if (ret) {
                        dev_warn(dev, "Error waiting for HPD GPIO: %d\n", ret);
-
-               return ret;
-       }
-
-       if (p->aux->wait_hpd_asserted) {
+                       goto error;
+               }
+       } else if (p->aux->wait_hpd_asserted) {

Hi Doug,

Acked-by: Jessica Zhang <quic_jessz...@quicinc.com>

Thanks,

Jessica Zhang

                ret = p->aux->wait_hpd_asserted(p->aux, HPD_MAX_US);

- if (ret)

+               if (ret) {
                        dev_warn(dev, "Controller error waiting for HPD: %d\n", 
ret);
-
-               return ret;
+                       goto error;
+               }
        }

/*

@@ -133,6 +131,12 @@ static int atana33xc20_resume(struct device *dev)
         * right times.
         */
        return 0;
+
+error:
+       drm_dp_dpcd_set_powered(p->aux, false);
+       regulator_disable(p->supply);
+
+       return ret;
  }

static int atana33xc20_disable(struct drm_panel *panel)

---
base-commit: b33651a5c98dbd5a919219d8c129d0674ef74299
change-id: 20240311-homestarpanel-regulator-f4b890ff4b7c

Best regards,
--
Douglas Anderson <diand...@chromium.org>