Fbdev rotation broken

[Derek Foreman]

On 17/03/15 07:34 AM, Pekka Paalanen wrote:
> On Tue, 17 Mar 2015 13:02:34 +0100
> Thilo Cestonaro <thilo at cestona.ro> wrote:
> 
>> Hey!
>>
>>> Just curious, why didn't you get the fbdev backend to work? Was it the
>>> color format thing?
>>>
>> No, I got the color format to work, but I need to rotate the screen, and 
>> the rotation in fbdev doesn't work as expected.
>> (I changed compositor-fbdev.c - weston_output_init() or so, to have the 
>> Transform which I wanted to try)
>>
>> Normal => 480x272
>> 180° => didn't do anything here, panel still placed like in normal
>> 90° => changed the image resolution to 272x480 but didn't rotate 
>> correctly, so half of the screen was invisible
>> 270° => like 90° but the other side was visible
>>
>> But as fbdev doesn't support Transformation from weston.ini, I guess 
>> this code isn't thought to be work, right?
>> Anyway I'm glad, drm with pixman backend is there! :)
> 
> Hmm, I wonder if we broke the fbdev backend recently with the output
> matrix stuff...
> 
> Fbdev-backend intends to do the rotation when blitting from shadow to
> front, but we already do the rotation when compositing to shadow.
> However, the matrix changes we did weren't supposed to change where
> each step is done, only the units, so I suppose this has been broken
> for a good while.
> 
> Given that it seems there is no way to rotate an fbdev output other
> than editing code, no-one certainly has tested it, and we should just
> remove the remaining code that pretends to support output rotation in
> compositor-fbdev.c. That might even fix it, too.

Wow, what a mess.  The flipped transforms can't have ever worked.

I've tried to fix and simplify it, as well as allow it to be configured
in the ini file.  I just posted the patch series to the list...