[PATCH] drm/amd/display: invalid parameter check in dmub_hpd_callback

[José Expósito]

The function performs a check on the "adev" input parameter, however, it
is used before the check.

Initialize the "dev" variable after the sanity check to avoid a possible
NULL pointer dereference.

Fixes: e27c41d5b0681 ("drm/amd/display: Support for DMUB HPD interrupt 
handling")
Addresses-Coverity-ID: 1493909 ("Null pointer dereference")
Signed-off-by: José Expósito <jose.exposit...@gmail.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index e727f1dd2a9a..7fbded7a6d9c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -656,7 +656,7 @@ void dmub_hpd_callback(struct amdgpu_device *adev, struct 
dmub_notification *not
        struct drm_connector_list_iter iter;
        struct dc_link *link;
        uint8_t link_index = 0;
-       struct drm_device *dev = adev->dm.ddev;
+       struct drm_device *dev;
 
        if (adev == NULL)
                return;
@@ -673,6 +673,7 @@ void dmub_hpd_callback(struct amdgpu_device *adev, struct 
dmub_notification *not
 
        link_index = notify->link_index;
        link = adev->dm.dc->links[link_index];
+       dev = adev->dm.ddev;
 
        drm_connector_list_iter_begin(dev, &iter);
        drm_for_each_connector_iter(connector, &iter) {
-- 
2.25.1