Re: [Linux-fbdev-devel] Some questions

[Antonino D. <ad...@po...>]

On Wed, 2003-03-05 at 22:16, Thomas Winischhofer wrote:
> 
> Further to my mail from a few minutes ago:
> 
> I wrote:
>  > But I noticed another issue here:
>  >
>  > When switching to gfx mode during boot (ie as soon as the penguin
>  > appears), the text console is aligned correctly at all edges, with all
>  > lines visible.
> 
>  > But when "initial console" starts, the mode is again changed, and now
>  > the last line of text is nearly invisible, its upper half appears at
>  > the lower screen edge, the lower half is below the screen's edge. The
>  > space between the penguin and the text is notably thicker.
>  >
>  > This can be recovered by switching to another VT and back. This makes
>  > the penguin disappear, and restores the console dimensions/edges to
>  > normal.
> 
>  > Interestingly, this only happens with 800x600; this mode is chosen
>  > upon requesting 800x592 (because of the font size). At 1024x768,
>  > everything is as it should.
> 
> I am almost sure that this has to do with the fact that I adapt var in 
> my check_var from 800x592 to 800x600. Console (or whoever) seems to 
> attempt to change the mode to its initially desired dimension on many 
> occasions.
> 

Strange.  If you boot at 800x600, the console will compute that as
100x37.  On fbcon_resize, it will request 800x592 but because the
difference is only 8, fb_set_var should be skipped, so no mode change
should happen throughout.  

> - This leads to the (unncessary) second mode switch during boot (when 
> the "initial console" starts), assumingly because the xres does not 
> match fontsize * rows,

At boot time, there are several times the display changes (not
necessarily mode changes) --  while the logo is being displayed, after
the logo got displayed, and during init.

> 
> - and probably is the reason for that vertical offset I see after this 
> mode switch: The text area on the screen is shifted down by exactly 8 
> pixels - 600-592=8
> 
> Any hints?
> 

I have no idea.  I booted with other drivers at 800x600 and get no ill
effects.  I get a margin at the bottom of 8 pixels.

How about checking what the offsets are during fb_pan_display()?

Tony