Hey Kyle, On Wed, Feb 3, 2021 at 8:48 AM Kyle Tso <kyletso@xxxxxxxxxx> wrote: > > On Thu, Feb 4, 2021 at 12:40 AM Benson Leung <bleung@xxxxxxxxxx> wrote: > > > > Hi Kyle, > > > > On Wed, Feb 3, 2021 at 7:39 AM Kyle Tso <kyletso@xxxxxxxxxx> wrote: > > > > > > Hi Prashant and Benson, > > > > > > I just got this notification that my patch "usb: pd: Update VDO > > > definitions" caused this build break. > > > The root cause is that I removed the definitions of Type-A and Type-B > > > in Product Type VDOs as they have already been deprecated. > > > And it's my bad that I didn't notice that someone else uses these definitions... > > > > > > I can fix it by simply removing them in the switch case but I am not > > > sure whether they need to be kept for some reason (compatibility ?) > > > What do you think? > > > > Strictly speaking, Type-A and Type-B definitions here are deprecated > > in PD 3.0, but PD 3.0 implementations have to be able to fall back to > > PD 2.0 protocol when the port partner or cable is PD 2.0 only. > > > > In the last version of the PD 2.0 specification released, the Type-A > > and Type-B definitions still remain, so we can't really remove them > > from the Kernel until all of PD 2.0 is deprecated. > > > > They're very rare cables, but I have seen a PD 2.0 cable with an > > e-marker that indicates Type-B here. > > > > Hope this helps, > > Benson > > > > -- > > Benson Leung > > Staff Software Engineer > > Chrome OS Kernel > > Google Inc. > > bleung@xxxxxxxxxx > > Chromium OS Project > > bleung@xxxxxxxxxxxx > > Thanks for the clarification! makes sense to me. > I will provide the fix as soon as possible. > > thanks, > Kyle There are actually other fields where this is problematic, if you just deleted a bunch of options that existed in PD 2.0 but not in PD 3.0. I posted a response on the list. Short summary: I think we need to bring back the whole set of PD 2.0 definitions in parallel with the PD 3.0 ones, and put switches everywhere based on pd_revision. Let me know if I can provide more help here. I saw this coming a little while ago, which is why I wanted to get the pd revision stuff in. Thanks, Benson -- Benson Leung Staff Software Engineer Chrome OS Kernel Google Inc. bleung@xxxxxxxxxx Chromium OS Project bleung@xxxxxxxxxxxx
