Forums - MSM72xxa woes

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MSM72xxa woes
Mario_Zechner
Join Date: 21 Oct 10
Posts: 2
Posted: Mon, 2010-11-01 05:39

Hi,

let me start of by saying that i love the Qualcomm developer site. I just discovered it recently and the information available along with the tools is pretty awesome. 

The reason i post is a bit negative though. Many Android phones out in the wild still sport the Qualcomm MSM72xxa variety of chips which uses an ATI GPU from what i could understand. This chip or its driver has some severe problems on Android. I would be the happiest person in the world if one of you Qualcomm engineers could help me out with some of them. For some of the problems i haven't yet prepared any testable code. If the need arises i can provide you with whatever it is you need.

  • The texture matrix stack is not working correctly.
  • Rendering non-screeen aligned quads in form of two triangles with either VBOs or VAs is slow. I guess the driver checks the current matrix stack, figures out it's an ortho projection and triggers a fast path for screen aligned quads. 
  • glSubBufferData is extremely slow, much slower than glBufferData which is a bit surprising. The use case is to replace portions or all of the currently bound VBO, e.g. for uploading skinned mesh data, CPU computed sprites etc. This is also true for the newer Adreno chips.
  • Calling glBufferData/glSubBufferData twice on a bound VBO results in memory corruption it seems. You can find a full description with source code at http://www.badlogicgames.com/wiki/index.php/Severe_Bug_Updating_Already_Bound_Buffer_Object.

This leads to seperate code paths for the MSM72xxa in many applications which is a tad bit undesireable. From the desktop i'm used to working around such bugs but i was hoping that it woudn't be such a huge deal on Android. Sadly it is.

Now i'm aware that the MSM72xxa is probably not used in any new handsets in the future. However, the devices that still sport it won't go away anytime soon. Are there any known work arounds for the problems above, besides the obvious ones? Are there any plans to give the driver's a little love and fix the problems? The biggest one is the last bullet point above.

Sorry for the wall of text. Looking forward to any feedback and answers.

Ciao,

Mario

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Steve L (not verified)
Posted: Wed, 2010-11-24 15:33

Unfortunately there are no plans for updating the 72xx drivers at this time.  We've received your comments though and have passed them along to the relevant parties internally, thank you for your feedback.

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Tim_Liquia
Join Date: 23 Mar 11
Posts: 3
Posted: Wed, 2011-03-23 18:01

I to am new to this forum, but have been using qualcomm chipsets in several phones that I have owned and developed for.  Over-all I have to say that your chipset's are great. I have owned several different devices with the MSM72xx chip, and all of them were extremely versitile and long lasting, thanks for that.

I see that you said that "Unfortunately there are no plans for updating the 72xx drivers at this time" which is dis-concerning to me. As a developer of custom OS for android, as a community we really need some help in this area. The phone that I am developing for is The MB200 Motorola cliq/dext. A few people from around the android community have been on a quest to find a way to improve our graphic experience. Unfortunately, we have tried several configurations to improve our graphics, and are only making minor advancements. A colleauge and myself have successfully compiled a working 2.3.3 OS for a phone that was never meant to see anything past android 2.1. These newer OS's that android keeps putting out requires the usage of better rendering software for our chipsets, but compatibility is always the issue. 

 My question would be this: So although I doubt strongly that the MSM7200A will ever have the capability to support openGL ES 2.0, but is there anything that I can do as a developer to improve the performance?  IE.....adding frame buffering or cube mapping, etc..... Also, what would you say is the best rendering software configuration that works best with this chipset?

I have been doing research and have discovered around 30 devices that use this chipset for CPU/GPU. If you total how many of those phones are out there in the world.......That is a heck of a lot of phones my friend, and owners that love and believe in your product.

Any information at all that you could give be would be greatly appreciated. Thanks again!

Tim Liquia

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