Hi Benson, On Wed, Aug 03, 2022 at 08:15:49AM -0700, Benson Leung wrote: > Hi Mika, > > On Tue, Aug 2, 2022 at 10:37 PM Mika Westerberg > <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > > > Hi, > > > > On Wed, Aug 03, 2022 at 06:31:39AM +0530, Rajat Khandelwal wrote: > > > Current implementation doesn't allow user to go into system suspend > > > and simultaneously project the screen on an external display connected > > > to a TBT/USB4 device. This patch enables this feature. > > > > > > Let me know what you think about this. > > > > Please prefix patches to follow the sybsystem style. For Thunderbolt it > > should be "thunderbolt: ....". > > > > This will cause any monitor plug to wake up the system and I'm not sure > > we want that, at least to be default behaviour. If you have a regular > > Type-C (non-USB4/TBT) dock and you plug in a monitor to that, does it > > wake up? > > Speaking for Google and our ChromeOS USB-C policy, yes, if the host is > in S0iX or S3, an already attached USB-C docking station in DP Alt > Mode will respond to a display attach via HPD via an Alert message in > USB PD. We called this feature wake-on-dock. > > We implemented wake-on-dock for DP Alt Mode in the EC, since our EC > handles USB PD anyway, and is handling the PD Alert message which > contains the HPD status. > > However, when the dock supports USB4 or Thunderbolt, those modes don't > involve USB PD for device attach, so our EC doesn't have the role of > waking the system, so something else on the system must, which is this > feature being discussed. Okay understood. Thanks for explaining!
