[Intel-gfx] [PATCH xf86-video-intel] sna: Replace the blt SYNC_COPY assert with a check

[Chris Wilson]

Quoting Ville Syrjala (2018-06-18 18:39:43)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> My IVB hits the SYNC_COPY assert in prefer_blt_copy() when I force the
> use of the software cursor and I move the cursor on top of a dri2
> window. Looks like any platform with sna_wait_for_scanline() implemented
> should be capable of tripping this assert.
> 
> Let's just replace the assert with a check, which is what gen6 already
> does. IVB/HSW/BDW have sna_wait_for_scanline() so we'll have to change
> the gen7 and gen8 code at least. gen9+ doesn't have sna_wait_for_scanline()
> so in theory we could leave that one be, but I like consistency so let's
> change that one too.

Hmm, my memory says that the assertion was concerned with making sure
the wait-for-event + copy operation was in the same batch. At any rate
it seems like the swcursor is breaking a few of my assumptions, so
before acting I'd like to tidy up the validation logic to check if it is
not working as intended.
-Chris