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Date: Tue, 20 Jul 2021 09:33:11 +0200 From: Geert Uytterhoeven <geert@...ux-m68k.org> To: Sam Ravnborg <sam@...nborg.org> Cc: David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>, Maxime Ripard <mripard@...nel.org>, Linux Fbdev development list <linux-fbdev@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, DRI Development <dri-devel@...ts.freedesktop.org> Subject: Re: [PATCH resend 0/5] video: fbdev: ssd1307fb: Optimizations and improvements Hi Sam, On Mon, Jul 19, 2021 at 9:23 PM Sam Ravnborg <sam@...nborg.org> wrote: > On Wed, Jul 14, 2021 at 04:57:59PM +0200, Geert Uytterhoeven wrote: > > 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. > > > > 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 your comments! > > > > 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_address_range() > > video: fbdev: ssd1307fb: Optimize screen updates > > video: fbdev: ssd1307fb: Cache address ranges > > A few comments left for a couple of patches. > The remaining patches are: > Acked-by: Sam Ravnborg <sam@...nborg.org> Thank you! > Do you have commit rights to drm-misc-next? No I have not (and I don't think I should). Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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