xref: /OK3568_Linux_fs/kernel/Documentation/fb/arkfb.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun========================================
2*4882a593Smuzhiyunarkfb - fbdev driver for ARK Logic chips
3*4882a593Smuzhiyun========================================
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun
6*4882a593SmuzhiyunSupported Hardware
7*4882a593Smuzhiyun==================
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun	ARK 2000PV chip
10*4882a593Smuzhiyun	ICS 5342 ramdac
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun	- only BIOS initialized VGA devices supported
13*4882a593Smuzhiyun	- probably not working on big endian
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun
16*4882a593SmuzhiyunSupported Features
17*4882a593Smuzhiyun==================
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun	*  4 bpp pseudocolor modes (with 18bit palette, two variants)
20*4882a593Smuzhiyun	*  8 bpp pseudocolor mode (with 18bit palette)
21*4882a593Smuzhiyun	* 16 bpp truecolor modes (RGB 555 and RGB 565)
22*4882a593Smuzhiyun	* 24 bpp truecolor mode (RGB 888)
23*4882a593Smuzhiyun	* 32 bpp truecolor mode (RGB 888)
24*4882a593Smuzhiyun	* text mode (activated by bpp = 0)
25*4882a593Smuzhiyun	* doublescan mode variant (not available in text mode)
26*4882a593Smuzhiyun	* panning in both directions
27*4882a593Smuzhiyun	* suspend/resume support
28*4882a593Smuzhiyun
29*4882a593SmuzhiyunText mode is supported even in higher resolutions, but there is limitation to
30*4882a593Smuzhiyunlower pixclocks (i got maximum about 70 MHz, it is dependent on specific
31*4882a593Smuzhiyunhardware). This limitation is not enforced by driver. Text mode supports 8bit
32*4882a593Smuzhiyunwide fonts only (hardware limitation) and 16bit tall fonts (driver
33*4882a593Smuzhiyunlimitation). Unfortunately character attributes (like color) in text mode are
34*4882a593Smuzhiyunbroken for unknown reason, so its usefulness is limited.
35*4882a593Smuzhiyun
36*4882a593SmuzhiyunThere are two 4 bpp modes. First mode (selected if nonstd == 0) is mode with
37*4882a593Smuzhiyunpacked pixels, high nibble first. Second mode (selected if nonstd == 1) is mode
38*4882a593Smuzhiyunwith interleaved planes (1 byte interleave), MSB first. Both modes support
39*4882a593Smuzhiyun8bit wide fonts only (driver limitation).
40*4882a593Smuzhiyun
41*4882a593SmuzhiyunSuspend/resume works on systems that initialize video card during resume and
42*4882a593Smuzhiyunif device is active (for example used by fbcon).
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun
45*4882a593SmuzhiyunMissing Features
46*4882a593Smuzhiyun================
47*4882a593Smuzhiyun(alias TODO list)
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun	* secondary (not initialized by BIOS) device support
50*4882a593Smuzhiyun	* big endian support
51*4882a593Smuzhiyun	* DPMS support
52*4882a593Smuzhiyun	* MMIO support
53*4882a593Smuzhiyun	* interlaced mode variant
54*4882a593Smuzhiyun	* support for fontwidths != 8 in 4 bpp modes
55*4882a593Smuzhiyun	* support for fontheight != 16 in text mode
56*4882a593Smuzhiyun	* hardware cursor
57*4882a593Smuzhiyun	* vsync synchronization
58*4882a593Smuzhiyun	* feature connector support
59*4882a593Smuzhiyun	* acceleration support (8514-like 2D)
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun
62*4882a593SmuzhiyunKnown bugs
63*4882a593Smuzhiyun==========
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun	* character attributes (and cursor) in text mode are broken
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun--
68*4882a593SmuzhiyunOndrej Zajicek <santiago@crfreenet.org>
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