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Many Issue with Mali 400 on A10 (Linux)

Piyush Verma
Note: This was originally posted on 17th August 2012 at http://forums.arm.com

Hi,

I am facing many problems with Mali 400. One of the big issue is lib is close source so can't change anything.

I am in advance stage of product development but stuck with many issues.

Point 1.

I was using Ericsson Texture Compression Mipmap Example and trying to work with normal RGBA texture.

Here is my load texture code.

/* Load just base level texture data. */
GL_CHECK(glGenTextures(1, &textureID));
GL_CHECK(glBindTexture(GL_TEXTURE_2D, textureID));
unsigned char *textureData = NULL;
Texture::loadData(texturePath.c_str(), &textureData);
    
GL_CHECK(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData));    

Here it just render a black area.

Just by referring RotoZoom program and with hit and try I fogure out it work if I add.

/* Set texture mode. */
GL_CHECK(glGenerateMipmap(GL_TEXTURE_2D));

after glTexImage2D.

Is glGenerateMipmap must to use texture ?
besides there is not any sample program which load basic rgba texture.

Point 2.
Besides with 2 or 3 test system give sigmentation fault continuously. Even is workable program.

Same program which was working before not work now and can work again on system restart.

Point 3.
EGLSwapbuffer is consuming 50% CPU. & I can't find any way to render directly to frame-buffer. Mali document say it's platform specific.
I can't understand FB interface is fix in all linux how come it could be platform specific ?.
Every body no most of vendor not support for anything like this.

Point 4.
http://www.arm.com/products/multimedia/mali-graphics-hardware/mali-400-mp.php
here mention 30M tri/s and up to 1.1G pix/s at 275MHz.

Correct me if I am wrong 1.1G Pix is filling pixels of screen with color or texture.

1.1 * 1000 *1000 *1000 / 1920 / 1080 / 60 = 8.84 Layers

if means if I render full hd @ 60 FPS I should be able to render full screen 8.84 times.

I am using a simple triangle program which is filling the screen and rendering 8 times in one round. then performance is dropping to 14fps.

Means 4 times slower than speq. where other points gpu is running on 320 Mhz not on 275 Mhz.

Point 5.

A very simple triangle program is not working in GLES1 so I am bound to use only GLES2.
As many places internet mention GLES1 is faster than GLES2.
There is not any sample program for GLES1. and document talk about gles1 simulator but there is not any gles1 simulator on mali website.


Point 6.

What is the process to get Mali 400 DDK Source.
Is it possible to get even after spending some money ?


Any clarification in above points can help us.

Thanks in Advance.


Regards

Piyush Verma
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  • Note: This was originally posted on 17th August 2012 at http://forums.arm.com

    Hi Piyush,

    for point 3 - how are you measuring this? Because the Mali GPU uses a deferred architecture, it is sometimes not unusual to see a seemlingly large amount of time in eglSwapBuffers(). The way the deferred architecture works, the driver collects all of the draw commands during the frame, but just adds them to a queue - it does not do actual rendering at the time of the glDraw*() call like an immediate mode renderer would. Instead, when the end of the frame is reached as indicated by eglSwapBuffers(), the driver will then work out the required drawing operations and execute them.

    Could this be what you are seeing?

    HTH, Pete
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  • Note: This was originally posted on 17th August 2012 at http://forums.arm.com

    Hi Piyush,

    for point 3 - how are you measuring this? Because the Mali GPU uses a deferred architecture, it is sometimes not unusual to see a seemlingly large amount of time in eglSwapBuffers(). The way the deferred architecture works, the driver collects all of the draw commands during the frame, but just adds them to a queue - it does not do actual rendering at the time of the glDraw*() call like an immediate mode renderer would. Instead, when the end of the frame is reached as indicated by eglSwapBuffers(), the driver will then work out the required drawing operations and execute them.

    Could this be what you are seeing?

    HTH, Pete
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