Re: [PATCH v4 15/38] drm/bridge: analogix_dp: Ensure edp is disabled when shutting down the panel

From: Marek Szyprowski
Date: Tue Mar 06 2018 - 02:35:40 EST


Hi All,

This is the patch, which introduces the issue I've pointed here:

https://lists.freedesktop.org/archives/dri-devel/2018-March/167794.html

On 2018-03-05 23:23, Enric Balletbo i Serra wrote:
From: Lin Huang <hl@xxxxxxxxxxxxxx>

When panel is shut down, we should make sure edp can be disabled to avoid
undefined behavior.

Cc: StÃphane Marchesin <marcheu@xxxxxxxxxxxx>
Signed-off-by: Lin Huang <hl@xxxxxxxxxxxxxx>
Signed-off-by: zain wang <wzz@xxxxxxxxxxxxxx>
Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
---

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 92fb9a072cb6..9b7d530ad24c 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1160,6 +1160,12 @@ static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
pm_runtime_get_sync(dp->dev);
+ ret = clk_prepare_enable(dp->clock);
+ if (ret < 0) {
+ DRM_ERROR("Failed to prepare_enable the clock clk [%d]\n", ret);
+ goto out_dp_clk_pre;
+ }
+
if (dp->plat_data->power_on)
dp->plat_data->power_on(dp->plat_data);
@@ -1191,6 +1197,8 @@ static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
phy_power_off(dp->phy);
if (dp->plat_data->power_off)
dp->plat_data->power_off(dp->plat_data);
+ clk_disable_unprepare(dp->clock);
+out_dp_clk_pre:
pm_runtime_put_sync(dp->dev);
return ret;
@@ -1234,10 +1242,13 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
disable_irq(dp->irq);
phy_power_off(dp->phy);
+ analogix_dp_set_analog_power_down(dp, POWER_ALL, 1);

In case of Exynos DP, external PHY is used to power the DP block, so no
register access should be performed after phy_power_off(). Please move
analogix_dp_set_analog_power_down() before phy_power_off().

if (dp->plat_data->power_off)
dp->plat_data->power_off(dp->plat_data);
+ clk_disable_unprepare(dp->clock);
+
pm_runtime_put_sync(dp->dev);
ret = analogix_dp_prepare_panel(dp, false, true);

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland