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

Sam Ravnborg sam at ravnborg.org
Tue Jul 20 14:45:41 UTC 2021


Hi Geert,
On Tue, Jul 20, 2021 at 09:33:11AM +0200, Geert Uytterhoeven wrote:
> Hi Sam,
> 
> On Mon, Jul 19, 2021 at 9:23 PM Sam Ravnborg <sam at ravnborg.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 at ravnborg.org>
> 
> Thank you!
> 
> > Do you have commit rights to drm-misc-next?
> 
> No I have not (and I don't think I should).
I would love to have you around for the fbdev stuff, as you knows a ton
more about fbdev than I do - I am just pretending.
And it would then be good if you could apply patches too. I for one may
be off for shorter or longer periods as this is purely driven by interest.

Note: I assume you will resend the series - then I can apply.

	Sam


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