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发表于 2014-6-16 17:42:54
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这个是驱动开发者的回复
Screen rotation can be partially accelerated, but it is never going to be as fast as non-rotated screen. The main problem is that the display controller does not directly support rotated scanout, so we need to have an intermediate temporary buffer for compositing everything and rotating it as an extra explicit step in the pipeline. Right now we have a software rotation implementation, inherited from xf86-video-fbdev. We could accelerate rotation with the help of G2D, but it is still an extra operation. Also we are going to have troubles with the video overlay, hardware cursor and other things. Quite a bit of work for something that is still not perfect.
It's best not to use the Xorg rotation. In some cases it could be avoided. For example, if you have a single full-screen GLES application, then the rotation can be done by Mali for free. |
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