[Intel-gfx] [PATCH v6 1/3] drm/i915/hdcp: update cp_irq_count_cached in intel_dp_hdcp2_read_msg()

[Kandpal, Suraj]

Hi ,

I have tested the patch 20856 against ci_drm_10499 and the patch 20921 against ci_drm_10537 kernel using the IGT kms_test_protection test on TGL platform with the following setups:
- HCDP2.2 Monitor connected to HDCP 2.2 Monitor
- HCDP2.2 Monitor connected to HDCP 1.4 Monitor
- HCDP1.4 Monitor connected to HDCP 1.4 Monitor
- HCDP2.2 Monitor standalone
- HDCP1.4 Monitor standalone 

I did not see any delta between the Patchwork and CI_DRM kernel and all DP MST Scenarios seem to work fine. We can go ahead and merge this patch.

 
Tested-by: Suraj K <suraj.kandpal at intel.com>

-----Original Message-----
From: Gupta, Anshuman <anshuman.gupta at intel.com> 
Sent: Thursday, September 2, 2021 6:38 PM
To: Li, Juston <juston.li at intel.com>; intel-gfx at lists.freedesktop.org; Kandpal, Suraj <suraj.kandpal at intel.com>
Cc: seanpaul at chromium.org; C, Ramalingam <ramalingam.c at intel.com>; Vivi, Rodrigo <rodrigo.vivi at intel.com>
Subject: RE: [Intel-gfx] [PATCH v6 1/3] drm/i915/hdcp: update cp_irq_count_cached in intel_dp_hdcp2_read_msg()



> -----Original Message-----
> From: Li, Juston <juston.li at intel.com>
> Sent: Friday, August 20, 2021 12:19 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: seanpaul at chromium.org; Gupta, Anshuman <anshuman.gupta at intel.com>; 
> C, Ramalingam <ramalingam.c at intel.com>; Vivi, Rodrigo 
> <rodrigo.vivi at intel.com>; Li, Juston <juston.li at intel.com>
> Subject: [Intel-gfx] [PATCH v6 1/3] drm/i915/hdcp: update 
> cp_irq_count_cached in intel_dp_hdcp2_read_msg()
> 
> Update cp_irq_count_cached when reading messages rather than when 
> writing a message to make sure the value is up to date and not stale 
> from a previously handled CP_IRQ.
> 
> AKE flow  doesn't always respond to a read with a ACK write msg.
> E.g. AKE_Send_Pairing_Info will "timeout" because we received a CP_IRQ 
> for reading AKE_Send_H_Prime but no write occurred between that and 
> reading AKE_Send_Pairing_Info so cp_irq_count_cached is stale causing 
> the wait to return right away rather than waiting for a new CP_IRQ.
> 
> Signed-off-by: Juston Li <juston.li at intel.com>
> Acked-by: Anshuman Gupta <anshuman.gupta at intel.com>
> Reviewed-by: Ramalingam C <ramalingam.c at intel.com>
Hi Suraj,
We don't have HDCP coverage in CI
Could you please provide your Tested-By tag after testing this patch series.
Br,
Anshuman 
> ---
>  drivers/gpu/drm/i915/display/intel_dp_hdcp.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> index d697d169e8c1..1d0096654776 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> @@ -446,8 +446,6 @@ static
>  int intel_dp_hdcp2_write_msg(struct intel_digital_port *dig_port,
>       void *buf, size_t size)
>  {
> -struct intel_dp *dp = &dig_port->dp;
> -struct intel_hdcp *hdcp = &dp->attached_connector->hdcp;  unsigned 
> int offset;
>  u8 *byte = buf;
>  ssize_t ret, bytes_to_write, len;
> @@ -463,8 +461,6 @@ int intel_dp_hdcp2_write_msg(struct 
> intel_digital_port *dig_port,  bytes_to_write = size - 1;  byte++;
> 
> -hdcp->cp_irq_count_cached = atomic_read(&hdcp->cp_irq_count);
> -
>  while (bytes_to_write) {
>  len = bytes_to_write > DP_AUX_MAX_PAYLOAD_BYTES ?
>  DP_AUX_MAX_PAYLOAD_BYTES :
> bytes_to_write; @@ -530,6 +526,8 @@ int intel_dp_hdcp2_read_msg(struct 
> intel_digital_port *dig_port,
>      u8 msg_id, void *buf, size_t size)  {  struct drm_i915_private 
> *i915 = to_i915(dig_port->base.base.dev);
> +struct intel_dp *dp = &dig_port->dp;
> +struct intel_hdcp *hdcp = &dp->attached_connector->hdcp;
>  unsigned int offset;
>  u8 *byte = buf;
>  ssize_t ret, bytes_to_recv, len;
> @@ -546,6 +544,8 @@ int intel_dp_hdcp2_read_msg(struct 
> intel_digital_port *dig_port,  if (ret < 0)  return ret;
> 
> +hdcp->cp_irq_count_cached = atomic_read(&hdcp->cp_irq_count);
> +
>  if (msg_id == HDCP_2_2_REP_SEND_RECVID_LIST) {  ret = 
> get_receiver_id_list_size(dig_port);
>  if (ret < 0)
> --
> 2.31.1