On Thu, Dec 19, 2024 at 11:33:50PM +0200, Jani Nikula wrote:
> The struct drm_dp_mst_topology_mgr *mgr parameter is only used for debug
> logging in case the passed in link rate or lane count are zero. There's
> no further error checking as such, and the function returns 0.
>
> There should be no case where the parameters are zero. The returned
> value is generally used as a divisor, and if we were hitting this, we'd
> be seeing division by zero.
>
> Just remove the debug logging altogether, along with the mgr parameter,
> so that the function can be used in non-MST contexts without the
> topology manager.
>
> Cc: Imre Deak <imre.deak@xxxxxxxxx>
> Cc: Lyude Paul <lyude@xxxxxxxxxx>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> [...]
> diff --git a/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c b/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c
> index 89cd9e4f4d32..ad29593d28cf 100644
> --- a/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c
> +++ b/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c
> @@ -199,10 +199,8 @@ static const struct drm_dp_mst_calc_pbn_div_test drm_dp_mst_calc_pbn_div_dp1_4_c
> static void drm_test_dp_mst_calc_pbn_div(struct kunit *test)
> {
> const struct drm_dp_mst_calc_pbn_div_test *params = test->param_value;
> - /* mgr->dev is only needed by drm_dbg_kms(), but it's not called for the test cases. */
> - struct drm_dp_mst_topology_mgr *mgr = test->priv;
>
> - KUNIT_EXPECT_EQ(test, drm_dp_get_vc_payload_bw(mgr, params->link_rate, params->lane_count).full,
> + KUNIT_EXPECT_EQ(test, drm_dp_get_vc_payload_bw(params->link_rate, params->lane_count).full,
> params->expected.full);
> }
Allocating the topology manager and setting kunit::priv isn't needed
then either, so that along with drm_dp_mst_helper_tests_init() should be
also removed. With that:
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
