Photoshop: How do I get a Smart Objects ACR edits back to Lightroom?

Nope, they're not that smart. Lightroom doesn't know what goes on outside of Lightroom.

When you chose Edit In>Open as Smart Object in Photoshop... you are, in essence, creating a new file (Tiff or PSD depending upon your settings).  At this point the new file branches from and no longer interacts with the original raw file used as the source. 

But I have the ACR prefs set to record edits into xmp files...where is that data going? Can't I make Lr read it?

No. You would need to open the raw file directly from Photoshop (bypassing Lightroom) in order for the XMP preference to come into play.  When you send the raw file to Photoshop as a Smart Object from Lightroom the resultant file is no longer a raw - it is a Tiff or PSD. 

Basically, if the Camera Raw dialog appears before you can edit the file (as when you open a raw from Photoshop), XMP is in play. If the Camera Raw dialog doesn't appear (as when  you send from Lightroom) then XMP is not in play. 

Fortunately it works like that....  For me the current operation is perfect, the. TIF or. PSD
 
Back in LR is completely independent, we can the broadcast such kind... it is the principle of the non-destructive treatment since the raw will still be available in the. PSD and can always be properly treated in CameraRaw, simply by editing the smart object.
Please  don't change anything!

Got it.  I was just hoping that layers opened as smart objects could keep their connection to the xmp files. I sometimes combine 2 or more different versions of an image from Lr as layers and sometimes in the middle of the process I like to edit one of the layers with ACR...but I see now that those edits are lost to Lr. And in fact lost to ACR too. You can only get to them in the PSD file.

And Yes, it is normal, there is disconnection from the database that is the catalogue!
 the. XMP are that a worse go, it is still better to all in the same file, so as a smart object.

I'm not sure why the experts here think this isn't possible, it is.

With xmp saved from LR, place the Raw file in Ps as a linked SO. When you double click that layer in Ps, and edit in ACR, the adjustments will save to the xmp which LR will then pickup.

and i just wanted to point out... the reason why so few people use or even know of this workflow is that neither the Br or Lr team has added an easy and obvious way to access it. I've been trying since linked SOs were first released to get the Br team to add Place as Linked SO's to the menu and contextuals, but the request has always fallen on deaf ears. Same goes for Lr... there needs to finally be a Place as Linked in Ps added to the Edit In contextual. Please?

More people would use it if they knew it was possible...

As ertho point out- you can use Lightroom to edit a Smart Object layer in Photoshop, but it involves a work-around method.

1. You need to save LR edits to the raw file as xmp  (Ctrl+S)
2. You need to "Place" the image into a Photoshop document by Menu: {File>Place Linked}. (So you need a background layer to be able to 'Place' - preferably the same pixel dimensions, and navigate folders to 'find' the image. )
3. You can then double-click the 'Placed' layer to edit in ACR.
4. Back in Lightroom you can then  Menu:  {Photo>Read Metadata from file} to update the LR view.
5. Further editing in Lightroom requires a "Save metadata" again to update the linked layer in PShop.


+1   "for Lr... there needs to finally be a Place as Linked in Ps added to the Edit In contextual. Please?"

I have found some weird behavior of Linked Smart Objects in Photoshop CC 2018:

When I change some settings and save them in Lightroom, Linked Smart Object (LSO) in Photoshop updates with default "zero" settings (in other words as if I reset all settings). If I double click LSO then in Adobe Camera RAW window I see all settings as they should be and after closing ACR window LSO updates with proper settings. If I continue to adjust image in Lightroom after that and save new settings again, then most of the time (if file is still opened in Photoshop) it updates properly. I keep "Auto update opened document" option turned on, Photoshop 19.1.1, Adobe Camera RAW 10.2.0.894, Lightroom Classic 7.2, Mac OS 10.11.6

Before that everything worked fine (I've created PS droplet with only one command "Update All modified content" and was able to update PS files without switching to Photoshop just by using "Edit In..." -> "My Droplet's name" and it worked as expected. Now it still work, but I get images with default settings instead of saved settings.

It's not just annoying issue for me, it potentially may create troubles because I'm working with big batches and may not notice sometimes that my image was updated with wrong settings and all my retouching layers over LSO are mismatching the background.

Any ideas how to solve that issue?

Option Dragging a file from Lightroom to the Photoshop canvas should created a Linked Smart Object.