kernel-ark/Documentation/fb
Eric Miao 198fc108ee [ARM] pxafb: add support for overlay1 and overlay2 as framebuffer devices
PXA27x and later processors support overlay1 and overlay2 on-top of the
base framebuffer (although under-neath the base is also possible). They
support palette and no-palette RGB formats, as well as YUV formats (only
available on overlay2). These overlays have dedicated DMA channels and
behave in a similar way as a framebuffer.

This heavily simplified and re-structured work is based on the original
pxafb_overlay.c (which is pending for mainline merge for a long time).

The major problems with this pxafb_overlay.c are (if you are interested
in the history):

  1. heavily redundant (the control logics for overlay1 and overlay2 are
     actually identical except for some small operations,  which are now
     abstracted into a 'pxafb_layer_ops' structure)

  2. a lot of useless and un-tested code (two workarounds which are now
     fixed on mature silicons)

  3. cursorfb is actually useless, hardware cursor should not be used
     this way, and the code was actually un-tested for a long time.

The code in this patch should be self-explanatory, I tried to add minimum
comments. As said, this is basically simplified, there are several things
still on the pending list:

  1. palette mode is un-supported and un-tested (although re-using the
     palette code of the base framebuffer is actually very easy now with
     previous clean-up patches)

  2. fb_pan_display for overlay(s) is un-supported

  3. the base framebuffer can actually be abstracted by 'pxafb_layer' as
     well, which will help further re-use of the code and keep a better
     and consistent structure. (This is the reason I named it 'pxafb_layer'
     instead of 'pxafb_overlay' or something alike)

See Documentation/fb/pxafb.txt for additional usage information.

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Cc: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Eric Miao <ycmiao@ycmiao-hp520.(none)>
2008-12-29 18:00:04 +08:00
..
cyblafb
00-INDEX fbdev: Update Documentation/fb/00-INDEX 2007-10-16 09:43:19 -07:00
arkfb.txt
aty128fb.txt
cirrusfb.txt
cmap_xfbdev.txt fbdev: defio and Metronomefb 2008-03-19 18:53:37 -07:00
deferred_io.txt fb: defio nopage 2008-02-06 10:41:15 -08:00
fbcon.txt
framebuffer.txt
gxfb.txt PM/gxfb: add hook to PM console layer that allows disabling of suspend VT switch 2008-04-28 08:58:36 -07:00
imacfb.txt
intel810.txt
intelfb.txt intelfb: support 945GME (as used in ASUS Eee 901) 2008-10-16 11:21:42 -07:00
internals.txt
lxfb.txt lxfb: disable suspend VT switch by default 2008-04-28 08:58:39 -07:00
matroxfb.txt
metronomefb.txt fbdev: platforming metronomefb and am200epd 2008-04-28 08:58:41 -07:00
modedb.txt update modedb.txt documentation about mode_option parameter change 2008-04-28 08:58:37 -07:00
pvr2fb.txt
pxafb.txt [ARM] pxafb: add support for overlay1 and overlay2 as framebuffer devices 2008-12-29 18:00:04 +08:00
s3fb.txt
sa1100fb.txt
sh7760fb.txt video: sh7760fb: SH7760/SH7763 LCDC framebuffer driver 2008-07-24 10:47:41 -07:00
sisfb.txt
sstfb.txt
tgafb.txt
tridentfb.txt tridentfb: documentation update 2008-07-24 10:47:37 -07:00
uvesafb.txt uvesafb: document mode to mode_option parameter change 2008-10-16 11:21:44 -07:00
vesafb.txt
viafb.modes viafb: viafb.modes, viafb.txt 2008-10-16 11:21:41 -07:00
viafb.txt viafb: viafb.modes, viafb.txt 2008-10-16 11:21:41 -07:00
vt8623fb.txt