Scrolling in LibreOffice Impress with enabled grid is very sluggish (EXA)
Submitted by Jan-Marek Glogowski
Assigned to xf86-video-ati maintainers
Created attachment 108968
Example presentation with grid enabled
With the attached presentation on a 120% zoom I see a fine grid for positioning (Disable via View - Grid - Display Grid). If it's switched on, scrolling is very sluggish. Same happens even without a grid in OOo 3.2.1 when moving a selected object, because the selection frame consists of many small diagonal lines. This is much better since LO 4.2, as it just draws a solid border (see attached PNGs).
The tests were done using LibreOffice 4.3.1 and OpenOffice.org 3.2.1 on Ubuntu 14.10 with oibaf repository:
libdrm2 - 2.4.58+git1411031830.00847f
mesa - 10.4~git1411050730.9e2473
xserver-xorg-video-radeon - 1:7.5.99+git1411032004.7c7b38
xserver-xorg-core - 2:1.16.0-1ubuntu1
linux-image-3.16.0-24-generic - 3.16.0-24.32
For the tests radeon was compiled with "#define RADEON_TRACE_FALL 1", which resulted in several of the following line:
EVERGREENCheckComposite: Component alpha not supported with source alpha and source value blending.
In an other test I also saw some of the following lines, but these don't seem related:
EVERGREENCheckCompositeTexture: Unsupported picture format 0x1011000
Hardware is a dual screen setup on a
Advanced Micro Devices, Inc. [AMD/ATI] Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM] (1002:6779)
Using the on-board Intel graphics, scrolling is fine.
As a workaround I set "EXAPixmaps" to "off", which basically disables most of the EXA HW Accel
It was mentioned on IRC by glennk and agd5f, that this might be the result of a SW fallback, which forces some buffer syncs via RAM and VRAM. Intel is fine, because it uses UMA.
Attachment 108968, "Example presentation with grid enabled":