NexusHD2 Android Forum

Odysseus wrote:2 days is outstanding! I never got better than a day when I had my HD2. If you're willing to experiment and see if you can do even better. instead of greenify or system monitor you may want to try "Snapdragon BatteryGuru" by Xiam Technologies, which is the software development arm of Qualcomm. I've been using it now for several weeks and it has increased the battery life of my Amaze by 20%.

soren wrote:Just out of curiosity, why do you force GPU rendering? I used to do this because I thought it would be faster but I didn't see any difference. On the contrary, I feel the apps launch faster (second time onward) when I disable HWUI for them.

gpietron wrote:out of curiosity, which I/O Scheduler are you using in this setup?

PoJD001 wrote:I have switched this on just recently, so still exploring. My naive understanding was that system apps would use GPU rendering too, which I was not sure is hapenning otherwise. I have not noticed any particular improvements either on this one.

ersinozler wrote:1. Black screen issue is spreading (Google Search + Currents App + Facebook App) (Workaround: disable apps' Hardware Acceleration via Hwa Settings - Not Helpfull)
The thing is: All these Apps. works fine on their welcome screen, but when you choice another section or make a search or select something, that new screen comes black but navigation buttons is visible and working.

soren wrote:I see. I want to optimize my HD2 so in the past I used to enable this option but I didn't notice any difference. Also, I thought that using HWA would make apps run faster but it seems that I was wrong. I use HWA Settings and it might just be a placebo effect but I feel that my HD2 runs smoother when I disable HWUI for a lot of apps.

Osprey00 wrote:tytung, is this anything useful?

0001-Forward-port-surface-dithering-from-CM10.2.patch


As I mentioned the other day, my theory is that it's related to Android's HTML rendering components. The screen goes black in Google Now/Search only when you do a search that requires web results. My guess is that the Currents and Facebook apps are querying the same HTML rendering component of Android. It makes it easier on the app developers, after all, to use web data whenever possible (especially when all of Facebook is on the web already, anyways), instead of needlessly duplicating everything in the app. If we can determine what that HTML rendering component is and either fix it or replace it, we'll likely fix all those apps that depend on it. That's my theory, at least. I believe that I read something about Google replacing the old WebView renderer with a Chromium-based one in KitKat (or something like that), so that could be the underlying change. Beyond that, I don't really know enough to pursue the problem solving much further, though. Hopefully, tytung can use this info to find the solution.

EDIT: To add to this, through some searching, I found that this is/was a problem on KitKat ROMs for other old phones, like the Desire HD (similar to the HD2) and the Nexus S. In a Nexus S thread, I found this guy's post:

http://forum.xda-developers.com/showpos ... tcount=366

That's what I was thinking, too, that the web renderer is making a call to graphics libraries that's failing. That would be why you get only a black square, yet you can click around on it to access the links that you can't see (meaning that the actual data is there).

Also, he followed up with this large post that suggests that he made some progress:

http://forum.xda-developers.com/showpos ... tcount=382

...then this one that suggests that the CM team fixed the bug:

http://forum.xda-developers.com/showpos ... tcount=393

I wonder why we're still seeing it, then. Could it be that they fixed it for devices that they officially support, like the Nexus S, but that code isn't making its way into our HD2 versions? I'm not sure what I'm talking about, but perhaps tytung can figure out what to do (if anything) with the information.

Odysseus wrote:This issue is also occurring on KitKat builds for the Amaze. As you mention it only appears to be affecting older legacy devices. As all of the similar "cousins" to the Amaze are affected as well. Your theory as to the cause has been postulated by several devs I've read on xda. As mentioned, it's probably related to Google changing the default rendering engine from WebKit to Chrome. There must be something in the Chrome codebase that isn't playing nicely with the older generation Andreno drivers our devices use. That's why newer devices are unaffected.

Osprey00 wrote:According to the last link that I posted, the problem seems to have been solved for devices with legacy PowerVR chips, like the Nexus S and Desire HD. Our HD2s have Adreno chips, but you have to think that the solution is either identical or very similar.

Odysseus wrote:Similar yes, identical no. The Adreno drivers and graphics engine our older devices use, were derived from ATI prior to their takeover by AMD (Adreno is an anagram of Radeon). After the ATI-AMD merger Qualcomm began furthering their Adreno graphics core independently of AMD. So each newer generation of Adreno has drifted further away from the Radeon base these processors began with. My take is Google developed KitKat with only the newest or upcoming graphic engines in mind. Since KitKat was not intended to run on our devices there was no backwards compatibility testing done to see if the new rendering engine broke older devices. It's going to take some cleaver development to get this sorted out, as Qualcomm is notorious for barely supporting the open source community. So even if they have the answers they're unlikely to reveal them publicly.