1097387 - Vsync Based Touch Resampling is choppier if preferences are enabled with edit-prefs.sh

Status: RESOLVED WORKSFORME

(Core Graveyard :: Widget: Gonk, defect)

Description

[Mason Chang [Inactive] [:mchang]]

+++ This bug was initially created as a clone of Bug #1062331 +++

After talking with gordon today, he said that touch resampling was choppier and jankier than without touch resampling enabled. I tried the same thing using the pvt builds from the b2g-qa flash tool and enabled the prefs via edit-prefs.sh. Indeed, touch resampling was worse than master whereas it is smooth with a local build and modifying the pref via b2g.js.

STR:
1) Download b2g flash tool
2) run flash_pvt.py -w
3) Flash with flame-kk, mozilla-central, engineering build, gecko+gaia.
4) Run edit-prefs.sh from a local b2g git repo, enable touch resampling.

Find out why there is a difference between enabling the pref locally versus with a pvt build.

Comment 1

[Mason Chang [Inactive] [:mchang]]

Now that bug 1085512 landed, I flashed following the steps from comment 0. I also verified that the preferences are indeed being read early enough from edit_prefs.sh such that they are valid by the time we initialize the hardware composer and touch input on the device. I enabled these prefs:

user_pref("gfx.touch.resample", true);
user_pref("gfx.vsync.compositor", true);
user_pref("gfx.vsync.hw-vsync.enabled", true);

And touch resampling seems to be working on the stock nightly via the B2G-Flash-Tool, updated today, Friday November 14 at 10:54 AM PST. Results from the B2g-Flash-Tool:

### Push Done.
Gaia-Rev        1e300eac2e56d98ad51d414766d031db7d33221f
Gecko-Rev       https://hg.mozilla.org/mozilla-central/rev/bbb68df450c2
Build-ID        20141114040205
Version         36.0a1
Device-Name     flame
FW-Release      4.4.2
FW-Date         Tue Nov 11 09:19:50 PST 2014
Bootloader      L1TC10011880

Gordon, can you try one last time, otherwise until Portland it is. Thanks!

Comment 2

[Gordon Brander :gordonb]

This seems to have fixed it. I don't see any of the visual janking that was happening previously.

It's hard to discern the increase in smoothness, but I do notice that touch responsiveness seems to significantly improve when these options are turned on. This may be an illusion due to the increase in smoothness. Either way, we're moving forward in quality!

Comment 3

[Mason Chang [Inactive] [:mchang]]

From comment 2, closing.