Hi Enrico,
On 2016-08-02 15:21, Enrico Weigelt, metux IT consult wrote: > I'm currently thinking about adding an hw-accelerated bitblt operation. > The idea goes like this: > > * we add some bitblt ioctl which copies rects between bo's. > (it also handles memory layouts, pixfmt conversion, etc) > * the driver can decide to let the GPU or IPU do that, if available > * if we have an suitable DMA engine (maybe only the more complex ones > which can handle lines on their own ...) we'll use that > * as fallback, resort to memcpy(). > > > Whether an dma engine can/should be used might be highly hw specific, > so that probably would be configured in DT. > > To use that feature, userland could actually allocate two BO's, > one that's mapped as a framebuffer to some crtc, another one just > a memory buffer. It could then render to the fast memory buffer and > tell the DRM to only copy over the changed regions to the graphics > memory via DMA (or whatever is best on that particular hw platform). > > > What do you think about that idea ? I'm working now on something similar, but more generic. There is already a framework for picture processing (converting, scaling, blitting, rotating) in Exynos DRM. It is called IPP (Image Post Processing), but its user interface is really ugly and limited, so I plan to rewrite it and make it really generic. Some discussion on it were already in the following thread: http://thread.gmane.org/gmane.linux.kernel.samsung-soc/49743 I plan to propose an API based on DRM object/properties, which will be similar to KMS atomic API. I will let you know when I have it ready for presenting in public. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
