* [PATCH] drm/panel-simple: Undo enable if HPD never asserts
@ 2021-01-15 1:22 Douglas Anderson
2021-01-15 2:09 ` Stephen Boyd
0 siblings, 1 reply; 2+ messages in thread
From: Douglas Anderson @ 2021-01-15 1:22 UTC (permalink / raw)
To: Thierry Reding, Sam Ravnborg
Cc: Rob Clark, David Airlie, linux-kernel, Douglas Anderson,
dri-devel, Stephen Boyd
If the HPD signal never asserts in panel_simple_prepare() and we
return an error, we should unset the enable GPIO and disable the
regulator to make it consistent for the caller.
At the moment I have some hardware where HPD sometimes doesn't assert.
Obviously that needs to be debugged, but this patch makes it so that
if I add a retry that I can make things work.
Fixes: 48834e6084f1 ("drm/panel-simple: Support hpd-gpios for delaying prepare()")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
drivers/gpu/drm/panel/panel-simple.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 71ae200ac48a..b89394b44f43 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -406,7 +406,7 @@ static int panel_simple_prepare(struct drm_panel *panel)
if (IS_ERR(p->hpd_gpio)) {
err = panel_simple_get_hpd_gpio(panel->dev, p, false);
if (err)
- return err;
+ goto error;
}
err = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio,
@@ -418,13 +418,19 @@ static int panel_simple_prepare(struct drm_panel *panel)
if (err) {
dev_err(panel->dev,
"error waiting for hpd GPIO: %d\n", err);
- return err;
+ goto error;
}
}
p->prepared_time = ktime_get();
return 0;
+
+error:
+ gpiod_set_value_cansleep(p->enable_gpio, 0);
+ regulator_disable(p->supply);
+
+ return err;
}
static int panel_simple_enable(struct drm_panel *panel)
--
2.30.0.284.gd98b1dd5eaa7-goog
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] drm/panel-simple: Undo enable if HPD never asserts
2021-01-15 1:22 [PATCH] drm/panel-simple: Undo enable if HPD never asserts Douglas Anderson
@ 2021-01-15 2:09 ` Stephen Boyd
0 siblings, 0 replies; 2+ messages in thread
From: Stephen Boyd @ 2021-01-15 2:09 UTC (permalink / raw)
To: Douglas Anderson, Sam Ravnborg, Thierry Reding
Cc: Rob Clark, David Airlie, Douglas Anderson, dri-devel, linux-kernel
Quoting Douglas Anderson (2021-01-14 17:22:59)
> If the HPD signal never asserts in panel_simple_prepare() and we
> return an error, we should unset the enable GPIO and disable the
> regulator to make it consistent for the caller.
>
> At the moment I have some hardware where HPD sometimes doesn't assert.
> Obviously that needs to be debugged, but this patch makes it so that
> if I add a retry that I can make things work.
>
> Fixes: 48834e6084f1 ("drm/panel-simple: Support hpd-gpios for delaying prepare()")
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
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