Bug 93541

Summary: [EXA] Audacity scrolling/zooming when zoomed in is painfully slow
Product: xorg Reporter: S. Christian Collins <s_chriscollins>
Component: Driver/RadeonAssignee: xf86-video-ati maintainers <xorg-driver-ati>
Status: RESOLVED MOVED QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium    
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description S. Christian Collins 2015-12-30 17:16:47 UTC 
Here is a video I made demonstrating this bug:
https://youtu.be/Mr7H1oy0x8Y

Steps to reproduce:
1) Open Audacity.
2) Drag an audio file into Audacity, preferably something at least a minute in length.
3) Use CTRL-mouse wheel to zoom in a little bit.
4) Drag the horizontal scrollbar back and forth. You should see smooth movement.
5) Zoom in further, even up to the sample level, but you don't need to go that far. You should notice the zooming operation start to get laggy.
6) Drag the horizontal scrollbar back and forth.

Result: The scrolling is unbearably choppy. On my system, the scrolling operation eats up an entire CPU core.

Expected result: The scrolling should be smooth and not eat an entire CPU core.

** My System **
OS: Kubuntu 14.04 64-bit w/ KDE SC 4.14.13
PC: HP Pavilion m6-1035dx
CPU/GPU: AMD A10-4600M APU with Radeon HD 7660G Graphics
RAM: 6GB DDR3 800 MHz
Linux Kernel: 3.16.0-57-generic
Screen Resolution: 1366 x 768

I have also tested this using a Kubuntu 15.10 live USB with the same results (not sure of kernel/xorg version used). I will be happy to do more tests if necessary.
Comment 1 S. Christian Collins 2015-12-30 17:18:37 UTC 
I forgot to mention: this bug does not occur using fglrx on the same system, nor does it occur on my desktop using the nvidia proprietary driver.
Comment 2 Alex Deucher 2015-12-31 16:41:24 UTC 
Does enabling glamor help?  Add:

Option "AccelMethod" "glamor"

To the device section of your xorg config.
Comment 3 S. Christian Collins 2016-01-05 01:39:55 UTC 
I can confirm that switching to "glamor" acceleration fixes this issue. Unfortunately, I get lots of screen tearing with glamor acceleration enabled.
Comment 4 Michel Dänzer 2016-01-07 07:48:08 UTC 
With current xf86-video-ati, Option "TearFree" should eliminate the tearing.

At this point I'm afraid it's unlikely that EXA performance issues will get fixed.
Comment 5 Martin Peres 2019-11-19 07:54:17 UTC 
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/xorg/driver/xf86-video-ati/issues/148.

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