On Thu, 2025-06-26 at 11:20 +0300, Imre Deak wrote:
> From: Imre Deak <imre.d...@gmail.com>
>
> Only those IRQs should be acked that are handled, however for SST all
> IRQs triggered by the sink are acked. This can be a problem for flags
> that are reserved/reading zero at a given moment, but become used for
> some purpose - with a side-effect if set - in a future DPCD revision.
>
> Fix the above by acking only those device service IRQs that will be
> handled. While at it add asserts that only the known/acked device
> service IRQs are handled both in the MST and SST case.
>
> Signed-off-by: Imre Deak <imre.d...@gmail.com>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 52249fa5c8a6d..6f67fac9724e1 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4537,6 +4537,14 @@ intel_dp_mst_disconnect(struct intel_dp *intel_dp)
> drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst.mgr, intel_dp->is_mst);
> }
>
> +#define INTEL_DP_DEVICE_SERVICE_IRQ_MASK_SST (DP_AUTOMATED_TEST_REQUEST | \
> + DP_CP_IRQ | \
> + DP_SINK_SPECIFIC_IRQ)
> +
> +#define INTEL_DP_DEVICE_SERVICE_IRQ_MASK_MST (DP_CP_IRQ | \
> + DP_DOWN_REP_MSG_RDY | \
> + DP_UP_REQ_MSG_RDY)
> +
> static bool
> intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *esi)
> {
> @@ -4628,6 +4636,8 @@ static bool
> intel_dp_get_and_ack_sink_irq_esi_sst(struct intel_dp *intel_dp, u8
> encoder->base.base.id, encoder->base.name,
> esi);
>
> + esi[1] &= INTEL_DP_DEVICE_SERVICE_IRQ_MASK_SST;
> +
> if (mem_is_zero(&esi[1], 3))
> return true;
>
> @@ -5172,6 +5182,8 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
> if (mem_is_zero(ack, sizeof(ack)))
> break;
>
> + drm_WARN_ON(display->drm, ack[1] &
> ~INTEL_DP_DEVICE_SERVICE_IRQ_MASK_MST);
> +
> if (!intel_dp_ack_sink_irq_esi(intel_dp, ack))
> drm_dbg_kms(display->drm, "Failed to ack ESI\n");
>
> @@ -5456,6 +5468,8 @@ static void intel_dp_handle_device_service_irq(struct
> intel_dp *intel_dp, u8 irq
> {
> struct intel_display *display = to_intel_display(intel_dp);
>
> + drm_WARN_ON(display->drm, irq_mask &
> ~INTEL_DP_DEVICE_SERVICE_IRQ_MASK_SST);
> +
> if (irq_mask & DP_AUTOMATED_TEST_REQUEST)
> intel_dp_test_request(intel_dp);
>
Evidently, this function is specific to SST irq. Wouldn't it be better
to have _sst in the name like in "intel_dp_check_mst_status()"? This
function is probably in an earlier patch, though, so if handled it
should be obviously be done there.
Otherwise:
Reviewed-by: Luca Coelho <luciano.coe...@intel.com>
--
Cheers,
Luca.
