Using QT with SGX to render without frame buffers (render to memory buffer for custom display)

Brent Bergan

Hello,

I have a custom board we have developed with custom FPGA-based video/display hardware. I'm currently using QT to render an On Screen Display using a modified svga screen driver example. I basically capture the data from the image in exposeRegion() and DMA this to the FPGA for display.

Now I would like to use the SGX hardware to render the widgets (HW accel) and DMA the rendered buffer to the FPGA. This configuration does not have linux frame buffers, therefore I need to be able to render to a pixel buffer or something similar. Is this possible by modifying the powervr graphics driver or eglnullws driver?

I'm currently using QT 4.8 with graphics-sdk_4.04.00.02.

Thanks!

over 12 years ago

0 Prabindh Sundareson over 12 years ago

TI__Expert 6580 points

You can try with livemem display plugin that was tested in an older version of Qt - refer to below post. But this can not use SGX for acceleration (-display powervr) as only one display plugin can be used with Qt.

http://tigraphics.blogspot.in/2010/05/qt-embedded-for-no-framebuffer-systems.html

0 Prathap Srinivas over 12 years ago in reply to Prabindh Sundareson

TI__Expert 5000 points

Hi,

If Qt is not a requirement, you can use pixmap(FBDEV=no while building graphics SDK). Below is a thread with more details on the same -

http://e2e.ti.com/support/dsp/omap_applications_processors/f/447/t/182475.aspx

Thanks,

Prathap.

0 Brent Bergan over 12 years ago in reply to Prathap Srinivas

Prodigy 20 points

Prathap,

Thank you for the quick replies. I am required to use QT currently. Our OSD has been developed in QT but the rendering is not fast enough so we've been trying to move to the SGX for rendering rather than SW rendering via our ported SVGA screen driver.

So I have a couple of questions:

1. Why wouldn't the FBDEV=0 not work for QT and just render to a cmem buffer? I haven't dug in enough yet so sorry if this is obvious.

2. If this could work, will there be significant performance improvement if I'm using standard widgets? I read on one of th wikis that acceleration of standard widgets via SGX is not currently supported, but you could use a graphics viewport to help with this acceleration.

It would be great if there was a method to use QT, accelerate rendering via SGX and also render to memory buffer versus a frame buffer. Our interface driver to our FPGA is a custom kernel module right now and I'm sure it would be a lot of work to move this to a framebuffer implementation.

0 Prathap Srinivas over 12 years ago in reply to Brent Bergan

TI__Expert 5000 points

Hi,

FBDEV=0 is different. That's a command line option provided during graphics SDK build for rendering to pixmap. Its for the null window system egl. Qt SGX acceleration is achieved with the standard powervr plugin provided by Qt & it uses frame buffer backend & QWS window system.

http://processors.wiki.ti.com/index.php/Qt_Tips

For Qt without frame buffer, livemem is the only option i can think of what Prabindh has already suggested in this thread.

Thanks,

Prathap.

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Using QT with SGX to render without frame buffers (render to memory buffer for custom display)