Re: [Intel-gfx] i915 HDCP 2.2 TX encryption on Teledyne test instrument

[Ramalingam C <ramalingam.c@intel.com>]

On 2020-04-29 at 18:12:32 +0000, Voldman, Mikhail wrote:
> Hi Ram,
> 
> Thank you for your help, in the past. 
> We can control HDCP on our products as needed.
> 
> One issue on the new motherboard used in our product.
> In this case, i915 advertises itself as DP-1 sink repeater and authenticated as HDCP 1.4 capable device, but downstream HDMI device is HDCP 2.3 capable and correctly authenticated as HDCP 2.3. 
I assume this is due to the lspcon used in your motherboard/SoC itself.
Which is converting DP->HDMI. For i915 LSPCon is external device
authenticate with it based on the LSPCon's hdcp capability and requested
HDCP type. And authentication between LSPCon and Display sink connected
to it is LSPCon's resposibility. I915 will assume LSPCon has followed
the HDCP spec for repeater.

-Ram
> Is it any way I can determine what HDCP level downstream device is authenticated?  
> Lock of i915 documentation makes this not very obvious. 
> Can you just point us in the right direction?
> 
> Tahk You,
> 
> Mikhail Voldman
> System Architect
> 
> Teledyne LeCroy, Protocol Solutions Group
> 2111 Big Timber Road
> Elgin, IL  60123
> email address:  mikhail.voldman@teledyne.com
> 847-888-0450 x136
> 
> Send me a file securely
> 
> 
> -----Original Message-----
> From: Ramalingam C <ramalingam.c@intel.com> 
> Sent: Tuesday, November 5, 2019 11:12 PM
> To: Voldman, Mikhail <Mikhail.Voldman@Teledyne.com>
> Cc: Kurmi Suresh Kumar <suresh.kumar.kurmi@intel.com>; intel-gfx <intel-gfx@lists.freedesktop.org>
> Subject: Re: i915 HDCP 2.2 TX encryption on Teledyne test instrument
> 
> ---External Email---
> 
> Moving to #intel-gfx
> 
> Hi,
> 
> Glad that I could help you!
> 
> On 2019-11-05 at 21:56:28 +0000, Voldman, Mikhail wrote:
> > Hello Ramalingam,
> > 
> > Thank you for quick response. 
> > Your information is very helpful. 
> > But can you elaborate:
> > 
> > In your product, If you want to enable the HDCP always based on the 
> > sink capability, set the "Content protection" to DESIRED state along 
> > with desired content type.  [MV] should I set DESIRED protection level as DRM master?
> This needs additional kernel patch for your product to set the desired state as default state of the property at the creation.
> > 
> > As these are properties, non DRM Masters can only read them. can set 
> > them. [MV] do you mean: " non DRM Masters can only read them, but  can't set them."
> Yes.
> > Can I use MEI interface to control HDCP?
> Not needed if you set the default state as desired.
> -Ram
> > 
> > Mikhail Voldman
> > System Architect
> > 
> > Teledyne LeCroy, Protocol Solutions Group
> > 2111 Big Timber Road
> > Elgin, IL  60123
> > Note new email address:  mikhail.voldman@teledyne.com
> > 847-888-0450 x136
> > 
> > Send me a file securely
> > 
> > 
> > -----Original Message-----
> > From: Ramalingam C <ramalingam.c@intel.com>
> > Sent: Monday, November 4, 2019 10:44 PM
> > To: Voldman, Mikhail <Mikhail.Voldman@Teledyne.com>
> > Cc: Kurmi Suresh Kumar <suresh.kumar.kurmi@intel.com>
> > Subject: Re: i915 HDCP 2.2 TX encryption on Teledyne test instrument
> > 
> > ---External Email---
> > 
> > On 2019-11-04 at 20:42:49 +0000, Voldman, Mikhail wrote:
> > > Hello Ramalingam,
> > > 
> > > We exchanged number of e-mails few months ago regarding Linux i915 HDCP 2.2 encryption  support in the new Teledyne video test instrument.
> > > Thanks for your help we were able to control HDCP 2.2 encryption as DRM masters.
> > > 
> > > Unfortunately our product requirement specified than we need to  enable HDCP 2.2 always if attached monitor capabilities shows HDCP 2.2 support.
> > > Also i915 based TX required to execute HDCP 2.2 re-authentication if Sink HPD is detected.
> > > 
> > > Is current Intel i915 kernel driver implementation can support desired functionality? Do you have plans to support this?
> > 
> > "HDCP always" will never be an upstream solution. always userspace 
> > driven.
> > 
> > In your product, If you want to enable the HDCP always based on the 
> > sink capability, set the "Content protection" to DESIRED state along 
> > with desired content type.
> > 
> > As these are properties, non DRM Masters can only read them. can set 
> > them.
> > 
> > Hope you are unblocked. All the best!
> > 
> > -Ram
> > > 
> > > Are current i915 allow control HDCP encryption by NOT DRM master application?
> > > 
> > > Any suggestion or advice by Intel HDCP 2.2 experts will be really appreciated.
> > > 
> > > Best Regards,
> > > 
> > > Mikhail Voldman
> > > System Architect
> > > [cid:image001.gif@01D2D0A7.919320A0]
> > > Teledyne LeCroy, Protocol Solutions Group
> > > 2111 Big Timber Road
> > > Elgin, IL  60123
> > > Note new email address:  
> > > mikhail.voldman@teledyne.com<mailto:mikhail.voldman@teledyne.com>
> > > 847-888-0450 x136
> > > 
> > > Send me a file 
> > > securely<https://transfereast.teledyne.com/filedrop/mikhail.voldman@
> > > teledyne.com>
> > > 
> > 
> > 
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