Bug 96607

Summary: [bisected] texture misrender / flicker in The Talos Principle on SKL
Product: Mesa Reporter: Grazvydas Ignotas <notasas>
Component: Drivers/DRI/i965Assignee: Jordan Justen <jljusten>
Status: RESOLVED FIXED QA Contact: Intel 3D Bugs Mailing List <intel-3d-bugs>
Severity: normal    
Priority: medium CC: jljusten
Version: git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: 0001-i965-Skip-update_texture_surface-when-the-plane-does.patch

Description Grazvydas Ignotas 2016-06-20 22:55:52 UTC 
Very similar symptoms to bug 96425 , but different cause. Turns out to be a regression:

commit 44997fc0c1cc7f24216e3b1c5d954919df946ee5
Author: Kristian Høgsberg Kristensen <kristian.h.kristensen@intel.com>
Date:   Sun May 1 21:20:02 2016 -0700

    i965: Support textures with multiple planes
    
    Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

Trace with grass incorrectly rendered on the last frame:
https://drive.google.com/file/d/0Bz8fw_SGGDzsendNRDc2U1BFdk0/view?usp=sharing

This hack seems to be enough to unbreak it:

--- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
@@ -911,8 +911,8 @@ brw_update_texture_surfaces(struct brw_context *brw)
    }
 
    if (fs) {
-      update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 1);
-      update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 2);
+      //update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 1);
+      //update_stage_texture_surfaces(brw, fs, &brw->wm.base, false, 2);
    }
 
    brw->ctx.NewDriverState |= BRW_NEW_SURFACES;
Comment 1 Jordan Justen 2016-06-20 23:08:38 UTC 
Created attachment 124631 [details] [review]
0001-i965-Skip-update_texture_surface-when-the-plane-does.patch

Does this patch help?
Comment 2 Grazvydas Ignotas 2016-06-20 23:31:29 UTC 
It does, thanks.

A 'Reported-by:' tag would be nice for bisection and hacking efforts :)
Comment 3 Alejandro Piñeiro (freenode IRC: apinheiro) 2016-06-27 07:23:47 UTC 
FWIW, the patch on comment #1 is already on master. Mentioning just in case this bug can be closed.
Comment 4 Grazvydas Ignotas 2016-06-27 22:08:44 UTC 
Yes, fixed by 727a9b24933d384f5440ed4318fb720ed11d6dd1 and 367cf3a2e3e51466429a6446ef14ed398a5fb948.

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