[PATCH 06/11] drm/vc4: hdmi: Handle error case of pm_runtime_resume_and_get

Stefan Wahren
2024-06-30T15:37:51Z

The commit 0f5251339eda ("drm/vc4: hdmi: Make sure the controller is
powered in detect") introduced the necessary power management handling
to avoid register access while controller is powered down.
Unfortunately it just print a warning if pm_runtime_resume_and_get()
fails and proceed anyway.

This could happen during suspend to idle. So we must assume it is unsafe
to access the HDMI register. So bail out properly.

Fixes: 0f5251339eda ("drm/vc4: hdmi: Make sure the controller is powered in detect")
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index d57c4a5948c8..b3a42b709718 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -429,6 +429,7 @@ static int vc4_hdmi_connector_detect_ctx(struct drm_connector *connector,
{
struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
enum drm_connector_status status = connector_status_disconnected;
+ int ret;

/*
* NOTE: This function should really take vc4_hdmi->mutex, but
@@ -441,7 +442,11 @@ static int vc4_hdmi_connector_detect_ctx(struct drm_connector *connector,
* the lock for now.
*/

- WARN_ON(pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev));
+ ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev);
+ if (ret) {
+ DRM_ERROR("Failed to retain HDMI power domain: %d\n", ret);
+ return status;
+ }

if (vc4_hdmi->hpd_gpio) {
if (gpiod_get_value_cansleep(vc4_hdmi->hpd_gpio))
--
2.34.1