On Sun, Apr 19, 2015 at 10:01 PM, Paolo Niccolò Giubelli
<paoloniccolo.giubelli@xxxxxxxxx> wrote:
> On Sun, Apr 19, 2015 at 9:29 PM, Geert Uytterhoeven
> <geert@xxxxxxxxxxxxxx> wrote:
>> On Sun, Apr 19, 2015 at 7:39 PM, Paolo Niccolò Giubelli
>> <paoloniccolo.giubelli@xxxxxxxxx> wrote:
>>> There's something wrong with the math, because i have a 1366x768x32
>>> FB, but my finfo.line_length (finfo is obtained via
>>> FBIOGET_FSCREENINFO) is 5504 bytes. Well, 5504/4 (4 is 4 bytes per
>>> pixel) is 1376 that is 10 pixels more than 1366.
>>
>> 1366 * 4 is not a multiple of 64. 5504 is.
>> I guess your hardware requires each line to start at an address which is a
>> multiple of 64.
>
> Thank you Geert! So I guess there's some kind of padding after the end
> of the line, where I can write anything that has no effect. Do you
> know if there's something to check into fb.h so to guess the alignment
> requirements?
The only way to find out is to look at fb_fix_screeninfo.line_length.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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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