[PATCH] drm/amd/display: Check return value of drm helper

[Harry Wentland]

On 2020-01-07 11:41 a.m., mikita.lipski at amd.com wrote:
> From: Mikita Lipski <mikita.lipski at amd.com>
> 
> If driver fails to update update VCPI allocation during
> compute_mst_dsc_configs_for_state - fail the function
> by early return.
> 
> Signed-off-by: Mikita Lipski <mikita.lipski at amd.com>

Reviewed-by: Harry Wentland <harry.wentland at amd.com>

Harry

> ---
>  .../display/amdgpu_dm/amdgpu_dm_mst_types.c   | 99 ++++++++++---------
>  1 file changed, 54 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> index 35c8b1469f4c..7911c5dac424 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> @@ -621,37 +621,41 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
>  
>  		if (initial_slack[next_index] > fair_pbn_alloc) {
>  			vars[next_index].pbn += fair_pbn_alloc;
> -			drm_dp_atomic_find_vcpi_slots(state,
> -						      params[next_index].port->mgr,
> -						      params[next_index].port,
> -						      vars[next_index].pbn,
> -						      dm_mst_get_pbn_divider(dc_link));
> +			if (drm_dp_atomic_find_vcpi_slots(state,
> +							  params[next_index].port->mgr,
> +							  params[next_index].port,
> +							  vars[next_index].pbn,\
> +							  dm_mst_get_pbn_divider(dc_link)) < 0)
> +				return;
>  			if (!drm_dp_mst_atomic_check(state)) {
>  				vars[next_index].bpp_x16 = bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
>  			} else {
>  				vars[next_index].pbn -= fair_pbn_alloc;
> -				drm_dp_atomic_find_vcpi_slots(state,
> -						      params[next_index].port->mgr,
> -						      params[next_index].port,
> -						      vars[next_index].pbn,
> -						      dm_mst_get_pbn_divider(dc_link));
> +				if (drm_dp_atomic_find_vcpi_slots(state,
> +								  params[next_index].port->mgr,
> +								  params[next_index].port,
> +								  vars[next_index].pbn,
> +								  dm_mst_get_pbn_divider(dc_link)) < 0)
> +					return;
>  			}
>  		} else {
>  			vars[next_index].pbn += initial_slack[next_index];
> -			drm_dp_atomic_find_vcpi_slots(state,
> -						      params[next_index].port->mgr,
> -						      params[next_index].port,
> -						      vars[next_index].pbn,
> -						      dm_mst_get_pbn_divider(dc_link));
> +			if (drm_dp_atomic_find_vcpi_slots(state,
> +							  params[next_index].port->mgr,
> +							  params[next_index].port,
> +							  vars[next_index].pbn,
> +							  dm_mst_get_pbn_divider(dc_link)) < 0)
> +				return;
>  			if (!drm_dp_mst_atomic_check(state)) {
>  				vars[next_index].bpp_x16 = params[next_index].bw_range.max_target_bpp_x16;
>  			} else {
>  				vars[next_index].pbn -= initial_slack[next_index];
> -				drm_dp_atomic_find_vcpi_slots(state,
> -						      params[next_index].port->mgr,
> -						      params[next_index].port,
> -						      vars[next_index].pbn,
> -						      dm_mst_get_pbn_divider(dc_link));
> +				if (drm_dp_atomic_find_vcpi_slots(state,
> +								  params[next_index].port->mgr,
> +								  params[next_index].port,
> +								  vars[next_index].pbn,
> +								  dm_mst_get_pbn_divider(dc_link)) < 0)
> +					return;
>  			}
>  		}
>  
> @@ -700,22 +704,24 @@ static void try_disable_dsc(struct drm_atomic_state *state,
>  			break;
>  
>  		vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps);
> -		drm_dp_atomic_find_vcpi_slots(state,
> -					      params[next_index].port->mgr,
> -					      params[next_index].port,
> -					      vars[next_index].pbn,
> -					      0);
> +		if (drm_dp_atomic_find_vcpi_slots(state,
> +						  params[next_index].port->mgr,
> +						  params[next_index].port,
> +						  vars[next_index].pbn,
> +						  0) < 0)
> +			return;
>  
>  		if (!drm_dp_mst_atomic_check(state)) {
>  			vars[next_index].dsc_enabled = false;
>  			vars[next_index].bpp_x16 = 0;
>  		} else {
>  			vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.max_kbps);
> -			drm_dp_atomic_find_vcpi_slots(state,
> -					      params[next_index].port->mgr,
> -					      params[next_index].port,
> -					      vars[next_index].pbn,
> -					      dm_mst_get_pbn_divider(dc_link));
> +			if (drm_dp_atomic_find_vcpi_slots(state,
> +							  params[next_index].port->mgr,
> +							  params[next_index].port,
> +							  vars[next_index].pbn,
> +							  dm_mst_get_pbn_divider(dc_link)) < 0)
> +				return;
>  		}
>  
>  		tried[next_index] = true;
> @@ -769,11 +775,12 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
>  		vars[i].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
>  		vars[i].dsc_enabled = false;
>  		vars[i].bpp_x16 = 0;
> -		drm_dp_atomic_find_vcpi_slots(state,
> -					      params[i].port->mgr,
> -					      params[i].port,
> -					      vars[i].pbn,
> -					      0);
> +		if (drm_dp_atomic_find_vcpi_slots(state,
> +						 params[i].port->mgr,
> +						 params[i].port,
> +						 vars[i].pbn,
> +						 0) < 0)
> +			return false;
>  	}
>  	if (!drm_dp_mst_atomic_check(state)) {
>  		set_dsc_configs_from_fairness_vars(params, vars, count);
> @@ -786,20 +793,22 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
>  			vars[i].pbn = kbps_to_peak_pbn(params[i].bw_range.min_kbps);
>  			vars[i].dsc_enabled = true;
>  			vars[i].bpp_x16 = params[i].bw_range.min_target_bpp_x16;
> -			drm_dp_atomic_find_vcpi_slots(state,
> -					      params[i].port->mgr,
> -					      params[i].port,
> -					      vars[i].pbn,
> -					      dm_mst_get_pbn_divider(dc_link));
> +			if (drm_dp_atomic_find_vcpi_slots(state,
> +							  params[i].port->mgr,
> +							  params[i].port,
> +							  vars[i].pbn,
> +							  dm_mst_get_pbn_divider(dc_link)) < 0)
> +				return false;
>  		} else {
>  			vars[i].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
>  			vars[i].dsc_enabled = false;
>  			vars[i].bpp_x16 = 0;
> -			drm_dp_atomic_find_vcpi_slots(state,
> -					      params[i].port->mgr,
> -					      params[i].port,
> -					      vars[i].pbn,
> -					      0);
> +			if (drm_dp_atomic_find_vcpi_slots(state,
> +							  params[i].port->mgr,
> +							  params[i].port,
> +							  vars[i].pbn,
> +							  0) < 0)
> +				return false;
>  		}
>  	}
>  	if (drm_dp_mst_atomic_check(state))
>