Created attachment 145310 [details]
test program, screenshots and debug traces
When I use glViewport with non-zero x,y with the lima driver, everything appears to be clipped at unexpected locations (which does not align with the viewport). I do not see this behavior with (for example) the llvmpipe driver.
I've attached a test program, a couple of screenshots (lima and llvmpipe output), the apitrace and other debug output. Both show a 320x240 window with glViewport(80,60,160,120) containing a triangle. Apitrace replay also displays as expected. A Full window viewport works as expected. The test program can be run with 4 arguments to change the arguments to glViewport.
For reference, this is running on an Allwinner R16 (aka A33 I think) which I gather has some rendition of Mali400 MP2.