[AD] Memory Bitmap to Display blit slow?

[Thomas Fjellstrom <tfjellstrom@xxxxxxxxxx>]

I've been noticing this for a while now, but under linux, with the nvidia 
binary drivers, bliting a memory bitmap to a regular allegro 5 display is 
horrendously slow.

Using SiegeLord's ex_prim example, when you change to software mode fps drops 
to 4fps on my (q6600+8800GTS) system. SiegeLord mentioned once that if you 
remove the final blit, the fps goes back up to normal, so it is not the 
software primitive rendering causing the slowdown. I'm confused as to why it 
would be so slow.

I tried setting the new bitmap format before creating the memory bitmap to the 
current display flags, but if it did help, it wasn't by much, maybe 1fps. So 
it doesn't seem to be a expensive conversion issue.  that leaves texture 
uploads being really slow, or the copy from the bitmap to a texture compatible 
data structure being the cause.

Anyone else have any ideas? As it is, bliting memory bitmaps to a display is 
unusable on my system right now.

Also, in a related note, when I turn the same example's blending off, the text 
disappears and the primitives change brightness.

-- 
Thomas Fjellstrom
tfjellstrom@xxxxxxxxxx