drm/amdgpu: fix NULL pointer dereference for Renoir

Commit c1cf79ca5ced46 ("drm/amdgpu: use IP discovery table for renoir")
introduced a NULL pointer dereference when booting with
amdgpu.discovery=0, because it removed the call of vega10_reg_base_init()
for that case.

Fix this by calling that funcion if amdgpu_discovery == 0 in addition to
the case that amdgpu_discovery_reg_base_init() failed.

Fixes: c1cf79ca5ced46 ("drm/amdgpu: use IP discovery table for renoir")
Signed-off-by: Dirk Gouders <dirk@gouders.net>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/soc15.c b/drivers/gpu/drm/amd/amdgpu/soc15.c
index 0de9df8..afcccc6 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/soc15.c
+++ b/drivers/gpu/drm/amd/amdgpu/soc15.c
@@ -662,12 +662,12 @@ static void soc15_reg_base_init(struct amdgpu_device *adev)
                 * it doesn't support SRIOV. */
                if (amdgpu_discovery) {
                        r = amdgpu_discovery_reg_base_init(adev);
-                       if (r) {
-                               DRM_WARN("failed to init reg base from ip discovery table, "
-                                        "fallback to legacy init method\n");
-                               vega10_reg_base_init(adev);
-                       }
+                       if (r == 0)
+                               break;
+                       DRM_WARN("failed to init reg base from ip discovery table, "
+                                "fallback to legacy init method\n");
                }
+               vega10_reg_base_init(adev);
                break;
        case CHIP_VEGA20:
                vega20_reg_base_init(adev);