[Linux-fbdev-devel] 2 pm3fb questions/problesm ...

[Sven L. <lu...@dp...>]

Hello, ...

I have yesterday tested pm3fbs latest incarnation, and have some questions
resulting from 2 problems there still are with it.

1) The Console cursor is working fine in depth 15, 16, 32. The blinking cursor
is using the revc, which uses a destination inverting blit. But the depth 8
currsor is not working correctly. It shows the right thing when the cursor is
blinked away, but when it should be there everything is black.

Now, the only difference is that depth 15, 16, 32 (well anything beside 8) is
in directcolor, while depth 8 is in CI8 (color index, pseudocolor in fbdev
speach). RGB332 could be used to solve this, but somehow i don't think this is
the right solution.

What i guess happens is that when inverting a pseudocolor framebuffer trough
the accel engine, the former color n get's inverted to !n or something such.

To solve this, one could simply write the inverted values of colors index 0 to
15 to index 255 to 250. This should work ok for the 16 bit color console, but
i guess there are some apps that use the full 256 colors, isn't it ?

Mmm, romain, now that i think of it, you could maybe try setting the
FBHardwareWriteMask to only affect the lower 16 bit, this would be 0x0f0f0f0f
i think. Could you try this ?

But again, altough this solves the 16 color useage, it will not work if you
use all 256 colors. And in this case, will the revc function be used ? I
simply don't know enough about the whle fbdev scheme to say more here, and
thus i ask for advice.

2) Juste after the vgacon -> fbcon switch there is some garbage on the screen
that get later scrolled up and disappears (though it remains beside the
pengouin logo). This garbage is alternated black and green columns, with some
chars in the green columns, which seems to be follow the ascii code, so i
guess this may be the font map or something such of the vga text console.

Now romain (which don't experience this, since he has powermac) did a cleaning
of the whole framebuffer memory at pm3fb initialisation time. No this resulted
in a clearing of the screen before the switch, but the garbage still stayed
there after the switch.

So, where is the right place to do this cleaning, and where do you think this
garbage could come from ? Is it a problem that needs to be solved by pm3fb, or
a more generic fbdev/fbcon stuff ? Ideally i think fbcon should clear the
framebuffer memory before using it.

That said, i am not sure about the origin of the stuff, why should it appear,
even if we did clean the framebuffer at initialisation time ? does vgacon put
it there before being removed ? Or is it the fbcon font map that get's
misplaced, or somethign such ?

3) Also in the same vein, what happens when we load/unload pm3fb as a module.
Especially, if we manage to revert to vgacon and it's text mode ? Will vgacon
restore the fonts and other stuff it needs, or should fbdev save and the
nrestore the fonts and stuff, as X does.

Hope this was not too long ...

Friendly,

Sven Luther