drm/amdgpu: fix error checking in amdgpu_read_mm_registers for nv

commit 8b2e097cf187d4b7bcceb4af5e59f08e8b033168 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/nv.c b/drivers/gpu/drm/amd/amdgpu/nv.c
index 6853b93ac82e763ca5910e2415d094c08298ab90..df3388e8dec004ab66f2abd16d0ba8dcc6bcae63 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/nv.c
+++ b/drivers/gpu/drm/amd/amdgpu/nv.c
@@ -393,9 +393,10 @@ static int nv_read_register(struct amdgpu_device *adev, u32 se_num,
        *value = 0;
        for (i = 0; i < ARRAY_SIZE(nv_allowed_read_registers); i++) {
                en = &nv_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 = nv_get_register_value(adev,