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authorOndrej Zajicek <santiago@crfreenet.org>2007-05-09 02:35:31 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-09 12:30:57 -0700
commit558b7bd86c32978648cda5deb5c758d77ef0c165 (patch)
tree4840567ca9496fe5bf0e9ac564650d613ae6c360 /Documentation
parentc3c117f06e95ea993ba4ed3b246fd76f87a4683f (diff)
vt8623fb: new framebuffer driver for VIA VT8623
This patch adds fbdev driver for graphics core in VIA VT8623 [adaplas@gmail.com: build fixes] Signed-off-by: Ondrej Zajicek <santiago@crfreenet.org> Signed-off-by: Antonino Daplas <adaplas@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/fb/vt8623fb.txt64
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diff --git a/Documentation/fb/vt8623fb.txt b/Documentation/fb/vt8623fb.txt
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+
+ vt8623fb - fbdev driver for graphics core in VIA VT8623 chipset
+ ===============================================================
+
+
+Supported Hardware
+==================
+
+ VIA VT8623 [CLE266] chipset and its graphics core
+ (known as CastleRock or Unichrome)
+
+I tested vt8623fb on VIA EPIA ML-6000
+
+
+Supported Features
+==================
+
+ * 4 bpp pseudocolor modes (with 18bit palette, two variants)
+ * 8 bpp pseudocolor mode (with 18bit palette)
+ * 16 bpp truecolor mode (RGB 565)
+ * 32 bpp truecolor mode (RGB 888)
+ * text mode (activated by bpp = 0)
+ * doublescan mode variant (not available in text mode)
+ * panning in both directions
+ * suspend/resume support
+ * DPMS support
+
+Text mode is supported even in higher resolutions, but there is limitation to
+lower pixclocks (maximum about 100 MHz). This limitation is not enforced by
+driver. Text mode supports 8bit wide fonts only (hardware limitation) and
+16bit tall fonts (driver limitation).
+
+There are two 4 bpp modes. First mode (selected if nonstd == 0) is mode with
+packed pixels, high nibble first. Second mode (selected if nonstd == 1) is mode
+with interleaved planes (1 byte interleave), MSB first. Both modes support
+8bit wide fonts only (driver limitation).
+
+Suspend/resume works on systems that initialize video card during resume and
+if device is active (for example used by fbcon).
+
+
+Missing Features
+================
+(alias TODO list)
+
+ * secondary (not initialized by BIOS) device support
+ * MMIO support
+ * interlaced mode variant
+ * support for fontwidths != 8 in 4 bpp modes
+ * support for fontheight != 16 in text mode
+ * hardware cursor
+ * video overlay support
+ * vsync synchronization
+ * acceleration support (8514-like 2D, busmaster transfers)
+
+
+Known bugs
+==========
+
+ * cursor disable in text mode doesn't work
+
+
+--
+Ondrej Zajicek <santiago@crfreenet.org>