4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tomasz Figa <tf...@chromium.org>

[ Upstream commit a4169609def769c66f88140678970b2be6f64ac7 ]

Driver callbacks, such as system suspend or resume can be called any
time, specifically they can be called before the component bind
callback. Let's use dp->adp pointer as a safeguard and skip calling
Analogix entry points if it is an ERR_PTR().

Signed-off-by: Tomasz Figa <tf...@chromium.org>
Signed-off-by: Thierry Escande <thierry.esca...@collabora.com>
Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
Tested-by: Marek Szyprowski <m.szyprow...@samsung.com>
Reviewed-by: Archit Taneja <arch...@codeaurora.org>
Signed-off-by: Andrzej Hajda <a.ha...@samsung.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20180423105003.9004-24-enric.balle...@collabora.com
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -358,6 +358,8 @@ static void rockchip_dp_unbind(struct de
        analogix_dp_unbind(dp->adp);
        rockchip_drm_psr_unregister(&dp->encoder);
        dp->encoder.funcs->destroy(&dp->encoder);
+
+       dp->adp = ERR_PTR(-ENODEV);
 }
 
 static const struct component_ops rockchip_dp_component_ops = {
@@ -381,6 +383,7 @@ static int rockchip_dp_probe(struct plat
                return -ENOMEM;
 
        dp->dev = dev;
+       dp->adp = ERR_PTR(-ENODEV);
        dp->plat_data.panel = panel;
 
        ret = rockchip_dp_of_probe(dp);
@@ -404,6 +407,9 @@ static int rockchip_dp_suspend(struct de
 {
        struct rockchip_dp_device *dp = dev_get_drvdata(dev);
 
+       if (IS_ERR(dp->adp))
+               return 0;
+
        return analogix_dp_suspend(dp->adp);
 }
 
@@ -411,6 +417,9 @@ static int rockchip_dp_resume(struct dev
 {
        struct rockchip_dp_device *dp = dev_get_drvdata(dev);
 
+       if (IS_ERR(dp->adp))
+               return 0;
+
        return analogix_dp_resume(dp->adp);
 }
 #endif


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