[Nouveau] [PATCH 4/8] acpi: Allow evaluate_optimus_dsm to take NULL results

[Samuel Pitoiset]

On 05/26/2015 12:22 AM, Pierre Moreau wrote:
> Signed-off-by: Pierre Moreau <pierre.morrow at free.fr>
> ---
>   drm/nouveau/nouveau_acpi.c | 10 ++++------
>   1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drm/nouveau/nouveau_acpi.c b/drm/nouveau/nouveau_acpi.c
> index 36f4a40..073f7d7 100644
> --- a/drm/nouveau/nouveau_acpi.c
> +++ b/drm/nouveau/nouveau_acpi.c
> @@ -88,15 +88,14 @@ static int nouveau_evaluate_optimus_dsm(acpi_handle handle, int func, int arg, u
>   	for (i = 0; i < 4; i++)
>   		args_buff[i] = (arg >> i * 8) & 0xFF;
>   
> -	*result = 0;
>   	obj = acpi_evaluate_dsm_typed(handle, nouveau_op_dsm_muid, nouveau_op_dsm_rid,
>   				      func, &argv4, ACPI_TYPE_BUFFER);
>   	if (!obj) {
>   		acpi_handle_info(handle, "failed to evaluate _DSM\n");
>   		return AE_ERROR;
>   	} else {
> -		if (obj->buffer.length == 4) {
> -			*result |= obj->buffer.pointer[0];
> +		if (!result && obj->buffer.length == 4) {
> +			*result  = obj->buffer.pointer[0];

segfault here if result is NULL! ;)

>   			*result |= (obj->buffer.pointer[1] << 8);
>   			*result |= (obj->buffer.pointer[2] << 16);
>   			*result |= (obj->buffer.pointer[3] << 24);
> @@ -322,18 +321,17 @@ void nouveau_register_dsm_handler(void)
>   /* Must be called for Optimus models before the card can be turned off */
>   void nouveau_switcheroo_optimus_dsm(void)
>   {
> -	u32 result = 0;
>   	if (!nouveau_dsm_priv.optimus_detected)
>   		return;
>   
>   	nouveau_evaluate_optimus_dsm(nouveau_dsm_priv.dhandle,
>   			             NOUVEAU_DSM_OPTIMUS_FLAGS,
> -			             0x3, &result);
> +			             0x3, NULL);
>   
>   	nouveau_evaluate_optimus_dsm(nouveau_dsm_priv.dhandle,
>   			             NOUVEAU_DSM_OPTIMUS_CAPS,
>   			             NOUVEAU_DSM_OPTIMUS_SET_POWERDOWN,
> -			             &result);
> +			             NULL);
>   
>   }
>