On Tue, Jul 20, 2021 at 11:16:27AM +0200, Geert Uytterhoeven wrote:
Hi Sam,
On Tue, Jul 20, 2021 at 9:56 AM Geert Uytterhoeven geert@linux-m68k.org wrote:
On Mon, Jul 19, 2021 at 9:21 PM Sam Ravnborg sam@ravnborg.org wrote:
On Wed, Jul 14, 2021 at 04:58:03PM +0200, Geert Uytterhoeven wrote:
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.
Reduce the amount of transferred data by only updating the rectangle that changed. Remove the call to ssd1307fb_set_address_range() during initialization, as ssd1307fb_update_rect() now takes care of that.
Note that for now the optimized operation is only used for fillrect, copyarea, and imageblit, which are used by fbcon.
Signed-off-by: Geert Uytterhoeven geert@linux-m68k.org
--- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -184,16 +184,18 @@ static int ssd1307fb_set_address_range(struct ssd1307fb_par *par, u8 col_start, return ssd1307fb_write_cmd(par->client, page_end); }
-static int ssd1307fb_update_display(struct ssd1307fb_par *par) +static int ssd1307fb_update_rect(struct ssd1307fb_par *par, unsigned int x,
unsigned int y, unsigned int width,unsigned int height){ struct ssd1307fb_array *array; u8 *vmem = par->info->screen_buffer; unsigned int line_length = par->info->fix.line_length;
unsigned int pages = DIV_ROUND_UP(par->height, 8);
unsigned int pages = DIV_ROUND_UP(height + y % 8, 8);Add () like this - at least it helps me:
unsigned int pages = DIV_ROUND_UP((height + y) % 8, 8);Thanks, that's actually a genuine bug.
No it's not "(height + y) % 8" is wrong.
Better if I reorder the operands like below?
unsigned int pages = DIV_ROUND_UP(y % 8 + height, 8);
Yep, then I would not be fooled so easy.
Sam