Re: fbcon gives mirrored fonts on monochrome display

Den 22.01.2015 20:59, skrev Geert Uytterhoeven:

Hi Noralf,

On Thu, Jan 22, 2015 at 8:55 PM, Noralf Trønnes [off-list ref] wrote:

quoted

Den 22.01.2015 20:44, skrev Geert Uytterhoeven:

quoted

On Thu, Jan 22, 2015 at 7:47 PM, Noralf Trønnes [off-list ref] wrote:

quoted

I'm playing with a SSD1306 128x64 monochrome display and fbcon gives me
mirrored fonts and some extra lines.
fbdev config:
    info->var.bits_per_pixel = 1;
    info->fix.visual = FB_VISUAL_MONO10;
    info->var.red.length = 1;
    info->var.red.offset = 0;
    info->var.green.length = 1;
    info->var.green.offset = 0;
    info->var.blue.length = 1;
    info->var.blue.offset = 0;
Uses: sys_fillrect, sys_copyarea, sys_imageblit (and deferred_io)

System: Raspberry Pi, ARM, Linux 3.18.3

Does anyone see what this might be?

What's the value on CONFIG_FB_CFB_REV_PIXELS_IN_BYTE in your .config?

$ zgrep CONFIG_FB_CFB_REV_PIXELS_IN_BYTE /proc/config.gz
# CONFIG_FB_CFB_REV_PIXELS_IN_BYTE is not set

quoted

Does your driver set FB_NONSTD_REV_PIX_IN_B?

No it doesn't. I also tried setting it now, with no effect:
info->var.nonstd = FB_NONSTD_REV_PIX_IN_B;

The latter only seems to matter if CONFIG_FB_CFB_REV_PIXELS_IN_BYTE
is set, so please try the config option first.

$ zgrep CONFIG_FB_CFB_REV_PIXELS_IN_BYTE /proc/config.gz
CONFIG_FB_CFB_REV_PIXELS_IN_BYTE=y

$ dmesg
[  365.595787]   nonstd = 2

It didn't change anything.

I looked up the code that is affected by this change, and only the 
cbf*.c files use the rev/swap/shift functions from fb_draw.h
I use the sys_* modules not cbf*
In principle the driver is like fb_ssd1307. It copies the framebuffer to 
RAM in the LCD controller at deferred_io intervals.