drm/amdgpu: fix error checking in amdgpu_read_mm_registers for soc21

commit 60b76fa95e4e8f070a485ee9be364cec7e4f36fe upstream.

Properly skip non-existent registers as well.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2442
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/soc21.c b/drivers/gpu/drm/amd/amdgpu/soc21.c
index 230e15fed755c92aba54b7cda1d22f3ab9a0be15..00df439ed493dc9ca740f5517131e02a9395783a 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/soc21.c
+++ b/drivers/gpu/drm/amd/amdgpu/soc21.c
@@ -254,9 +254,10 @@ static int soc21_read_register(struct amdgpu_device *adev, u32 se_num,
        *value = 0;
        for (i = 0; i < ARRAY_SIZE(soc21_allowed_read_registers); i++) {
                en = &soc21_allowed_read_registers[i];
-               if (adev->reg_offset[en->hwip][en->inst] &&
-                   reg_offset != (adev->reg_offset[en->hwip][en->inst][en->seg]
-                                  + en->reg_offset))
+               if (!adev->reg_offset[en->hwip][en->inst])
+                       continue;
+               else if (reg_offset != (adev->reg_offset[en->hwip][en->inst][en->seg]
+                                       + en->reg_offset))
                        continue;
 
                *value = soc21_get_register_value(adev,