Bug 98508 - Some linear gradients are broken
Summary: Some linear gradients are broken
Alias: None
Product: xorg
Classification: Unclassified
Component: Server/Acceleration/glamor (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Xorg Project Team
QA Contact: Xorg Project Team
Depends on:
Reported: 2016-10-30 19:41 UTC by Clemens Eisserer
Modified: 2018-02-01 07:40 UTC (History)
0 users

See Also:
i915 platform:
i915 features:

self-contained testcase (2.58 KB, text/plain)
2016-10-30 19:41 UTC, Clemens Eisserer
no flags Details
Expected output (21.50 KB, image/png)
2018-01-23 16:45 UTC, Michel Dänzer
no flags Details
Bad output (209 bytes, image/png)
2018-01-23 16:45 UTC, Michel Dänzer
no flags Details
testcase covering all 4 repeat types/linear & radial/2 stops & 8 stops (5.05 KB, text/x-csrc)
2018-02-01 05:25 UTC, Jeff Smith
no flags Details

Description Clemens Eisserer 2016-10-30 19:41:26 UTC
Created attachment 127630 [details]
self-contained testcase

Some linear gradients are broken when rendered using a AMD Mullins based laptop with glamor. 

The attached test-case should render a blue-red-blue gradient (at least that is intended and works on intel-sna), however with radeon+glamor it is mostly red.
Comment 1 Clemens Eisserer 2016-10-30 19:42:29 UTC
forgot to mention: the laptop is running an updated fedora-24 installation, with Xorg version: 

X.Org X Server 1.18.4
Release Date: 2016-07-19
Comment 2 Michel Dänzer 2016-10-31 03:44:22 UTC
Building xserver with


in glamor/glamor_priv.h commented out avoids the problem.
Comment 3 Michel Dänzer 2018-01-23 16:45:27 UTC
Created attachment 136920 [details]
Expected output
Comment 4 Michel Dänzer 2018-01-23 16:45:57 UTC
Created attachment 136921 [details]
Bad output
Comment 5 Jeff Smith 2018-01-26 14:58:16 UTC
I finished tracking down the cause of this reflect-repeat linear gradient bug.  In the process of testing it, I ran across another issue with no-repeat gradients.  Fixes for those, and some other code cleanup can be found in this patch series:

Comment 6 Jeff Smith 2018-02-01 05:25:55 UTC
Created attachment 137102 [details]
testcase covering all 4 repeat types/linear & radial/2 stops & 8 stops
Comment 7 Michel Dänzer 2018-02-01 07:17:35 UTC
Thanks for the report, fixed with https://cgit.freedesktop.org/xorg/xserver/commit/?id=3e377e238f7257fd01e56a4a25dfd77e033673e4 .
Comment 8 Clemens Eisserer 2018-02-01 07:40:24 UTC

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