Re: [PATCH v2 0/5] video: fbdev: ssd1307fb: Optimizations and improvements

[Sam Ravnborg <sam@ravnborg.org>]

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