Hi, At what speed are you running the SPI bus?
Theoretical fps for a 176x220 RGB565 display at 32MHZ: 32*1024*1024/176/220/16 = 54fps Try modetest to see max fps: https://github.com/notro/panel-mipi-dbi/wiki/Debugging#modetest I don't remember the command line switch to have it run continously showing the fps. Noralf. Den 04.08.2025 09:54, skrev Josef Luštický: > Hello, > is it possible to use GPU acceleration with TinyDRM drivers? > I am testing on STM32MP157c SoC with Vivante GC400 GPU and I use > Mesa3D 24.0.9 (rootfs generated with Buildroot 2025.02.3) and kernel > 5.10.176. > > To compare, I also have the same system but with a MIPI DSI display. > While kmscube renders at 60 fps with the MIPI DSI display, I get only > 11 fps with the SPI display (TinyDRM driver). > > Is there some architectural limitation, either in Mesa, kernel, or HW-related? > I suppose both setups use kernel's KMS as renderer only (kmsro), thus > it should render at the same framerate into framebuffer. > The difference in HW is the peripheral the displays use - MIPI DSI > display utilizes LTDC peripheral (kmscube loads > /usr/lib/dri/stm_dri.so) vs. SPI display uses just SPI (ksmcube loads > /usr/lib/dri/ili9225_dri.so). Both .so files are hard links. > Both open /dev/dri/renderD128 (GPU). > > The MIPI DSI display is connected to the DSI Host peripheral which > just transcodes the parallel RGB pixel stream from the LTDC (LCD > Timing Display Controller) peripheral of the STM SoC. > The display driver is drivers/gpu/drm/panel/panel-sitronix-st7703.c (DRM > panel). > > The SPI display driver uses the kernel's TinyDRM API and its driver is > drivers/gpu/drm/tiny/ili9225.c , but I can change to any other driver > if needed (eventually to the generic panel-mipi-dbi-spi). > Could rewriting the TinyDRM driver to a panel driver in > drivers/gpu/drm/panel/ help? > > I also tried software rendering "softpipe" (disabled GPU in > device-tree) and it renders 7 fps on both systems. Thus, I suppose, > that some form of GPU acceleration is already used. > > Mesa reports the same loaded GL-extensions on both systems and apart > from loaded .so files everything seems to be the same. > > Best regards > Josef Lusticky
