On Wed, 25 Sep 2024, Suraj Kandpal <[email protected]> wrote: > Retry the first read and write to downstream at least 10 times > with a 50ms delay if not hdcp2 capable. The reason being that
What are the 10 times and 50 ms delay based on? > during suspend resume Dock usually keep the HDCP2 registers inaccesible > causing AUX error. This wouldn't be a big problem if the userspace > just kept retrying with some delay while it continues to play low > values content but most userpace applications end up throwing an error > when it receives one from KMD. This makes sure we give the dock > and the sink devices to complete its power cycle and then try HDCP > authentication. > > Signed-off-by: Suraj Kandpal <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_hdcp.c | 26 +++++++++++++++++------ > 1 file changed, 19 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c > b/drivers/gpu/drm/i915/display/intel_hdcp.c > index 2afa92321b08..5f2383c219e8 100644 > --- a/drivers/gpu/drm/i915/display/intel_hdcp.c > +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c > @@ -1512,7 +1512,7 @@ static int hdcp2_authentication_key_exchange(struct > intel_connector *connector) > } msgs; > const struct intel_hdcp_shim *shim = hdcp->shim; > size_t size; > - int ret; > + int ret, i; > > /* Init for seq_num */ > hdcp->seq_num_v = 0; > @@ -1522,13 +1522,25 @@ static int hdcp2_authentication_key_exchange(struct > intel_connector *connector) > if (ret < 0) > return ret; > > - ret = shim->write_2_2_msg(connector, &msgs.ake_init, > - sizeof(msgs.ake_init)); > - if (ret < 0) > - return ret; > + for (i = 0; i <= 10; i++) { I'm pretty nitpicky about this. Please avoid <= in the for loop if you can. Just make it the obvious (i = 0; i < 10; i++), or if you have 1 try + 10 retries, then i < 10 + 1 or i < 11. If the 10 retries is just made up, then maybe just try 10 times total. > + if (!intel_hdcp2_get_capability(connector)) { > + msleep(50); > + continue; > + } This changes behaviour for the first try too. Is that intentional? No mention in the commit message? > + > + ret = shim->write_2_2_msg(connector, &msgs.ake_init, > + sizeof(msgs.ake_init)); > + if (ret < 0) > + continue; > + > + ret = shim->read_2_2_msg(connector, HDCP_2_2_AKE_SEND_CERT, > + &msgs.send_cert, > sizeof(msgs.send_cert)); > + if (ret < 0) > + continue; > + else The else is redundant here. > + break; > + } > > - ret = shim->read_2_2_msg(connector, HDCP_2_2_AKE_SEND_CERT, > - &msgs.send_cert, sizeof(msgs.send_cert)); > if (ret < 0) > return ret; -- Jani Nikula, Intel
