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Message-ID: <20240325145626.3.I552e8af0ddb1691cc0fe5d27ea3d8020e36f7006@changeid>
Date: Mon, 25 Mar 2024 14:56:27 -0700
From: Douglas Anderson <dianders@...omium.org>
To: dri-devel@...ts.freedesktop.org
Cc: Pin-yen Lin <treapking@...omium.org>,
Prahlad Kilambi <prahladk@...gle.com>,
Hsin-Yi Wang <hsinyi@...omium.org>,
Douglas Anderson <dianders@...omium.org>,
Daniel Vetter <daniel@...ll.ch>,
David Airlie <airlied@...il.com>,
Jessica Zhang <quic_jesszhan@...cinc.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Neil Armstrong <neil.armstrong@...aro.org>,
Sam Ravnborg <sam@...nborg.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] drm-panel: If drm_panel_dp_aux_backlight() fails, don't fail panel probe
If we're using the AUX channel for eDP backlight and it fails to probe
for some reason, let's _not_ fail the panel probe.
At least one case where we could fail to init the backlight is because
of a dead or physically missing panel. As talked about in detail in
the earlier patch in this series, ("drm/panel-edp: If we fail to
powerup/get EDID, use conservative timings"), this can cause the
entire system's display pipeline to fail to come up and that's
non-ideal.
If we fail to init the backlight for some transitory reason, we should
dig in and see if there's a way to fix this (perhaps retries?). Even
in that case, though, having a panel whose backlight is stuck at 100%
(the default, at least in the panel Samsung ATNA33XC20 I tested) is
better than having no panel at all.
Signed-off-by: Douglas Anderson <dianders@...omium.org>
---
If needed, I could split this into two patches: one for each of the
two panels that use drm_panel_dp_aux_backlight(). Since they both go
through drm-misc, though, it doesn't feel worth it.
drivers/gpu/drm/panel/panel-edp.c | 8 +++++++-
drivers/gpu/drm/panel/panel-samsung-atna33xc20.c | 9 +++++++--
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c
index 607cdd6feda9..0bf66d9dd5b8 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -944,8 +944,14 @@ static int panel_edp_probe(struct device *dev, const struct panel_desc *desc,
err = drm_panel_dp_aux_backlight(&panel->base, panel->aux);
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);
+
+ /*
+ * Warn if we get an error, but don't consider it fatal. Having
+ * a panel where we can't control the backlight is better than
+ * no panel.
+ */
if (err)
- goto err_finished_pm_runtime;
+ dev_warn(dev, "failed to register dp aux backlight: %d\n", err);
}
drm_panel_add(&panel->base);
diff --git a/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
index 9c336c71562b..6828a4f24d14 100644
--- a/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
+++ b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
@@ -328,9 +328,14 @@ static int atana33xc20_probe(struct dp_aux_ep_device *aux_ep)
ret = drm_panel_dp_aux_backlight(&panel->base, aux_ep->aux);
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);
+
+ /*
+ * Warn if we get an error, but don't consider it fatal. Having
+ * a panel where we can't control the backlight is better than
+ * no panel.
+ */
if (ret)
- return dev_err_probe(dev, ret,
- "failed to register dp aux backlight\n");
+ dev_warn(dev, "failed to register dp aux backlight: %d\n", ret);
drm_panel_add(&panel->base);
--
2.44.0.396.g6e790dbe36-goog
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