On Tue, 23 Mar 2004, James Simmons wrote:

quoted

What is this change to fb_write() in your tree ? It looks very
wrong to me. You are removing the ability for the driver to
hook it's own fb_write function, which can be a problem. You
basically assume copy_from_user() can be used straight with
the framebuffer as a destination.

Look again. The idea was to grab the userland data and create struct
fb_image then use xxxfb_imageblit to draw for you. We should never
allow fb_write and fb_read to directly access the framebuffer.

Speaking of. We really need to cleanup the fb_write and crap.
The program flow should be:

fb_write -> xxxfb_imageblit -> fb_pixmap.outbuf();

The outbuf and inbuf commands should replace the fb_writeX and fb_readX
stuff. This way driver developers can still use the cfb_xxx functions for
strange hardware. a good example is the Epson 1335 chip. You can only
access the framebuffer 16 bits at a time. Using 32 bit transfers will drop
have the data. Why epson did this will never be know.

   The other bonus with using the imageblit method with fb_write is
that we can treat planar modes a packed pixel modes :-)

Never thought about that one...

So if your application doesn't support the frame buffer format, it can use
write() instead of mmap() and just use packed pixels in a shadow frame buffer.

But what about read()? There's no imageget() method.

Do we want to support writev() as well? That would be useful for drawing
rectangular images.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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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