| Message ID | 20210727134730.3765898-1-geert@linux-m68k.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | video: fbdev: ssd1307fb: Optimizations and improvements | expand |
Hi Geert, On Tue, Jul 27, 2021 at 03:47:25PM +0200, Geert Uytterhoeven wrote: > Hi all, > > This patch series optimizes console operations on ssd1307fb, after the > customary fixes and cleanups. > > Currently, each screen update triggers an I2C transfer of all screen > data, up to 1 KiB of data for a 128x64 display, which takes at least 20 > ms in Fast mode. While many displays are smaller, and thus require less > data to be transferred, 20 ms is still an optimistic value, as the > actual data transfer may be much slower, especially on bitbanged I2C > drivers. After this series, the amount of data transfer is reduced, as > fillrect, copyarea, and imageblit only update the rectangle that > changed. > > Changes compared to v1[1]: > - Add Acked-by, > - Use two separate helpers instead of a single combined helper, > - Reorder operands in DIV_ROUND_UP() to improve readability. > > This has been tested on an Adafruit FeatherWing OLED with an SSD1306 > controller and a 128x32 OLED, connected to an OrangeCrab ECP5 FPGA board > running a 64 MHz VexRiscv RISC-V softcore, where it reduced the CPU > usage for blinking the cursor from more than 70% to ca. 10%. > > Thanks for applying! Thanks for the respin - patches are now applied to drm-misc-next. Sam
Hi all, This patch series optimizes console operations on ssd1307fb, after the customary fixes and cleanups. Currently, each screen update triggers an I2C transfer of all screen data, up to 1 KiB of data for a 128x64 display, which takes at least 20 ms in Fast mode. While many displays are smaller, and thus require less data to be transferred, 20 ms is still an optimistic value, as the actual data transfer may be much slower, especially on bitbanged I2C drivers. After this series, the amount of data transfer is reduced, as fillrect, copyarea, and imageblit only update the rectangle that changed. Changes compared to v1[1]: - Add Acked-by, - Use two separate helpers instead of a single combined helper, - Reorder operands in DIV_ROUND_UP() to improve readability. This has been tested on an Adafruit FeatherWing OLED with an SSD1306 controller and a 128x32 OLED, connected to an OrangeCrab ECP5 FPGA board running a 64 MHz VexRiscv RISC-V softcore, where it reduced the CPU usage for blinking the cursor from more than 70% to ca. 10%. Thanks for applying! [1] https://lore.kernel.org/dri-devel/20210714145804.2530727-1-geert@linux-m68k.org Geert Uytterhoeven (5): video: fbdev: ssd1307fb: Propagate errors via ssd1307fb_update_display() video: fbdev: ssd1307fb: Simplify ssd1307fb_update_display() video: fbdev: ssd1307fb: Extract ssd1307fb_set_{col,page}_range() video: fbdev: ssd1307fb: Optimize screen updates video: fbdev: ssd1307fb: Cache address ranges drivers/video/fbdev/ssd1307fb.c | 151 ++++++++++++++++++++++---------- 1 file changed, 104 insertions(+), 47 deletions(-)