fbcon gives mirrored fonts on monochrome display

fbcon gives mirrored fonts on monochrome display

[Noralf Trønnes]

Hi,

I'm playing with a SSD1306 128x64 monochrome display and fbcon gives me 
mirrored fonts and some extra lines.
Running fbtest gives me the expected output.

fbtest dump: http://tronnes.org/downloads/fbtest.png

fbcon dump: http://tronnes.org/downloads/fbcon.png
The text should have been:
Raspbian GNU/Lin

raspberrypi logi

fbcon font:VGA8x8: http://tronnes.org/downloads/fbcon8x8.png

ProFont6x11 gives indecipherable text lines: 
http://tronnes.org/downloads/fbcon6x11.png

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?


Regards,
Noralf Trønnes

Re: fbcon gives mirrored fonts on monochrome display

[Geert Uytterhoeven]

Hi Noralf,

On Thu, Jan 22, 2015 at 7:47 PM, Noralf Trønnes <notro@tronnes.org> wrote:
> 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?
Does your driver set FB_NONSTD_REV_PIX_IN_B?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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

Re: fbcon gives mirrored fonts on monochrome display

[Noralf Trønnes]

Hi Geert,

Den 22.01.2015 20:44, skrev Geert Uytterhoeven:
> Hi Noralf,
>
> On Thu, Jan 22, 2015 at 7:47 PM, Noralf Trønnes <notro@tronnes.org> wrote:
>> 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

> 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;

Re: fbcon gives mirrored fonts on monochrome display

[Geert Uytterhoeven]

Hi Noralf,

On Thu, Jan 22, 2015 at 8:55 PM, Noralf Trønnes <notro@tronnes.org> wrote:
> Den 22.01.2015 20:44, skrev Geert Uytterhoeven:
>> On Thu, Jan 22, 2015 at 7:47 PM, Noralf Trønnes <notro@tronnes.org> wrote:
>>> 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
>
>> 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.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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

Re: fbcon gives mirrored fonts on monochrome display

[Noralf Trønnes]

Den 22.01.2015 20:59, skrev Geert Uytterhoeven:
> Hi Noralf,
>
> On Thu, Jan 22, 2015 at 8:55 PM, Noralf Trønnes <notro@tronnes.org> wrote:
>> Den 22.01.2015 20:44, skrev Geert Uytterhoeven:
>>> On Thu, Jan 22, 2015 at 7:47 PM, Noralf Trønnes <notro@tronnes.org> wrote:
>>>> 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
>>
>>> 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.

Re: fbcon gives mirrored fonts on monochrome display

[Geert Uytterhoeven]

Hi Noralf,

On Thu, Jan 22, 2015 at 9:38 PM, Noralf Trønnes <notro@tronnes.org> wrote:
> Den 22.01.2015 20:59, skrev Geert Uytterhoeven:
>> On Thu, Jan 22, 2015 at 8:55 PM, Noralf Trønnes <notro@tronnes.org> wrote:
>>> Den 22.01.2015 20:44, skrev Geert Uytterhoeven:
>>>> On Thu, Jan 22, 2015 at 7:47 PM, Noralf Trønnes <notro@tronnes.org>
>>>> wrote:
>>>>> I'm playing with a SSD1306 128x64 monochrome display and fbcon gives me
>>>>> mirrored fonts and some extra lines.

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

One more thing that's no longer in sync...
Ideally, the cfb* and sys* versions are identical, except that the former
operates on MMIO, and the latter on RAM.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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

Re: fbcon gives mirrored fonts on monochrome display

[Noralf Trønnes]

Den 22.01.2015 21:42, skrev Geert Uytterhoeven:
> Hi Noralf,
>
> On Thu, Jan 22, 2015 at 9:38 PM, Noralf Trønnes <notro@tronnes.org> wrote:
>> Den 22.01.2015 20:59, skrev Geert Uytterhoeven:
>>> On Thu, Jan 22, 2015 at 8:55 PM, Noralf Trønnes <notro@tronnes.org> wrote:
>>>> Den 22.01.2015 20:44, skrev Geert Uytterhoeven:
>>>>> On Thu, Jan 22, 2015 at 7:47 PM, Noralf Trønnes <notro@tronnes.org>
>>>>> wrote:
>>>>>> I'm playing with a SSD1306 128x64 monochrome display and fbcon gives me
>>>>>> mirrored fonts and some extra lines.
>>>> $ zgrep CONFIG_FB_CFB_REV_PIXELS_IN_BYTE /proc/config.gz
>>>> # CONFIG_FB_CFB_REV_PIXELS_IN_BYTE is not set
>>>>
>>>>> 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*
> One more thing that's no longer in sync...
> Ideally, the cfb* and sys* versions are identical, except that the former
> operates on MMIO, and the latter on RAM.

Ok, so I'm out of luck, unless I patch this up myself :-) (which didn't 
look very complicated btw, as you say they look very similar)

Thanks for your help.


Noralf.