Messages in this thread | | | Date | Thu, 28 Jul 2005 23:39:08 +0200 (CEST) | From | Geert Uytterhoeven <> | Subject | Re: [Linux-fbdev-devel] Re: [PATCH] fbdev: colormap fixes |
| |
On Thu, 28 Jul 2005, Jon Smirl wrote: > I've verified now that all ATI R300+ chips have 10bit cmaps. These are > pretty common so I'd be in favor of making this into a binary > attribute where I can get/set the whole table at once. Given that > OpenGL is already supporting 12 and 16 bits these tables are only > going to get much larger. > > 1024 entries * 5 fields * 2 bytes = 10KB -- too big for a text attribute. > > 65536 entries * 5 fields * 2 bytes = 655KB -- way too big for a text attribute. > > The bits_per_pixel sysfs attribute is an easy way to tell how many > entries you need. You can just set it at 4, 8, 10, etc until you get > an error. Now you know the max. 2^n and you know how many entries.
No, bits_per_pixel can be (much) larger than the color map size. E.g. a simple ARGB8888 directcolor mode has bits_per_pixel = 32 and color map size = 256.
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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |