Re: [PATCH 2/2] drm/i915/hdcp: Drop mgr->base.lock acquisition in intel_conn_to_vcpi()

["Reddy Guddati, Santhosh" <santhosh.reddy.guddati@intel.com>]

Hi Suraj,

LGTM,
Tested-by: Santhosh Reddy Guddati <santhosh.reddy.guddati@intel.com>
Reviewed-by: Santhosh Reddy Guddati <santhosh.reddy.guddati@intel.com>

On 30-04-2026 08:59, Suraj Kandpal wrote:
> Now that intel_conn_to_vcpi() reads the MST topology state via
> drm_atomic_get_new_mst_topology_state(), the topology state belongs
> to this atomic commit and is already serialized through the atomic
> state's private object machinery. There is no need to additionally
> take mgr->base.lock here.
> Taking it from the HDCP enable path in commit_tail with
> state->base.acquire_ctx is also unsafe: by this point the
> acquire_ctx is no longer in a state where new modeset locks may be
> acquired through it, which produces a modeset-lock splat on MST +
> HDCP. Drop the drm_modeset_lock() call.
> 
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_hdcp.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index 91d2d7d823cc..a5d4e77f810f 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -80,9 +80,8 @@ static int intel_conn_to_vcpi(struct intel_atomic_state *state,
>   	/* For HDMI this is forced to be 0x0. For DP SST also this is 0x0. */
>   	if (!connector->mst.port)
>   		return 0;
> -	mgr = connector->mst.port->mgr;
>   
> -	drm_modeset_lock(&mgr->base.lock, state->base.acquire_ctx);
> +	mgr = connector->mst.port->mgr;
>   	mst_state = drm_atomic_get_new_mst_topology_state(&state->base, mgr);
>   	if (!mst_state) {
>   		drm_dbg_kms(display->drm, "MST topology still not created\n");