On Tue, Apr 29, 2025 at 12:57:16PM +0200, Aleksandrs Vinarskis wrote: > On Tue, 29 Apr 2025 at 10:03, Johan Hovold <[email protected]> wrote: > > > > On Tue, Apr 29, 2025 at 10:50:55AM +0300, Abel Vesa wrote: > > > On 25-04-29 09:23:46, Johan Hovold wrote: > > > > On Mon, Apr 28, 2025 at 05:17:21PM +0300, Abel Vesa wrote: > > > > > On 25-04-28 14:47:04, Johan Hovold wrote: > > > > > > On Mon, Apr 28, 2025 at 11:06:39AM +0200, Aleksandrs Vinarskis > > > > > > wrote: > > > > > > > On Mon, 28 Apr 2025 at 09:45, Johan Hovold <[email protected]> > > > > > > > wrote: > > > > > > > > > > Does this mean that the incomplete LTTPR support in 6.15-rc1 > > > > > > > > broke > > > > > > > > adapters or docks with retimers in transparent mode? > > > > > > Ok, but my concern is if they may have worked in a default transparent > > > > mode. > > > > > > But if they are by default in transparent mode, doing the setup to > > > transparent mode will not break it in any way. > > > > It looks like it will, see below. > > > > > > > X13s doesn't have LTTPRs on-board so when reading the caps, LTTPRs > > > > > count > > > > > would return 0 and none of the of the transparent/non-transparent > > > > > setup > > > > > would happen. > > > > > > > > But this is the crux; does any off-board LTTPRs in transparent mode add > > > > to the count or not? If they don't, how would you ever learn that there > > > > are any LTTPRs? If they do, it seems we may have a problem here. > > > > > > Count gets increased either way. It doesn't matter if they are in > > > transparent mode or not. > > > > Thanks for confirming. So then it seems we do have a problem as since > > 6.15-rc1 drm_dp_lttpr_init() will switch all LTTPRs to non-transparent > > mode. > > In this case, let me add Fixes to the entire series. Do you think we > could land it in 6.15-rcX then? The second option proposed to roll > back current LTTPR support and wait until 6.16 will completely break > DP output on all X1E, so it's very undesirable.
It should be possible, if you rebase onto 6.15-rc, add Fixes tags and send it quickly enough. > This series was tested quite a bit on at least the X1E/X1P devices, > both with and without docking stations, as it is also (v2 iirc) part > of Ubuntu's concept tree since little over a month ago. You have > confirmed that x13s also works with this change but without a docking > station. If someone could confirm that x13s with this change does work > with a docking station as well, it would be safe to merge the entire > series as fix to 6.15, correct? I could reach out on #aarch64-laptops, > perhaps someone has both x13s (or another qcom-based non X1(E) device) > and a docking station. > > Thanks, > Alex > > > > > Johan -- With best wishes Dmitry
