From mboxrd@z Thu Jan 1 00:00:00 1970
From: bugzilla-daemon@freedesktop.org
Subject: [Bug 84662] New: Long pauses with Unreal demo Elemental on R9270X
since : Always flush the HDP cache before submitting a CS to the GPU
Date: Sat, 04 Oct 2014 14:50:48 +0000
Message-ID:
Bug ID
84662
Summary
Long pauses with Unreal demo Elemental on R9270X since : Alwa=
ys flush the HDP cache before submitting a CS to the GPU
Product
Mesa
Version
git
Hardware
Other
OS
All
Status
NEW
Severity
normal
Priority
medium
Component
Drivers/Gallium/radeonsi
Assignee
dri-devel@lists.freedesktop.org
Reporter
adf.lists@gmail.com
R9270X PCIE 2.0 2 gig vram 4 gig ram.
Unreal demo Elemental only recently started working with git llvm/mesa, do =
no
bisection done on these.
The demo even when working is very broken - constant 1/4 sec stutters with a
couple of 1/2 - 1 sec.
But after -
commit 4439d469706699b4e69ef410ebc9115339f6e9e6
Author: Michel D=C3=A4nzer <michel.daenzer@amd.com>
Date: Thu Jul 31 18:43:49 2014 +0900
drm/radeon: Always flush the HDP cache before submitting a CS to the GPU
This ensures the GPU sees all previous CPU writes to VRAM, which makes =
it
safe:
* For userspace to stream data from CPU to GPU via VRAM instead of GTT
* For IBs to be stored in VRAM instead of GTT
* For ring buffers to be stored in VRAM instead of GTT, if the HPD flush
is performed via MMIO
There are far longer pauses of many seconds - run time to unreal logo on &q=
uot;good"
is 3:45 on bad best 5:39 can be longer.
Screens to be attached show quite different vram/gtt usage between good and
bad.
Related to=20
https://bugs.freedesktop.org/show_bug.c=
gi?id=3D82050
I bisected to the same commit in that bug, but applying the mesa patch
https://bugs.freedesktop.org/show_b=
ug.cgi?id=3D82050#c19
doesn't help here.
CONFIG_CMA is not set.
Tried kernel org 3.17-rc7 as it was reported in above as working, but not f=
or
me.