[PATCH] fbdev driver for S3 Trio/Virge

Add a driver for S3 Trio / S3 Virge.  Driver is tested with most versions
of S3 Trio and with S3 Virge/DX, on i386.

(akpm: We kind-of have support for this hardware already, but...

virgefb.c
  - amiga/zorro specific,
  - broken (according to Kconfig),
  - uses obsolete/nonexistent interface (struct display_switch)
  - recent Adrian Bunk's patch removes this driver

S3triofb.c
  - ppc/openfirmware specific
  - minimal functionality
  - broken (according to Kconfig),
  - uses obsolete/nonexistent interface (struct display_switch)
)

Signed-off-by: Ondrej Zajicek <santiago@crfreenet.org>
Cc: James Simmons <jsimmons@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 78 insertions, 0 deletions

diff --git a/Documentation/fb/s3fb.txt b/Documentation/fb/s3fb.txt
new file mode 100644
index 000000000000..8a04c0da0c91
--- /dev/null
+++ b/Documentation/fb/s3fb.txt
@@ -0,0 +1,78 @@
+
+        s3fb - fbdev driver for S3 Trio/Virge chips
+        ===========================================
+
+
+Supported Hardware
+==================
+
+        S3 Trio32
+        S3 Trio64 (and variants V+, UV+, V2/DX, V2/GX)
+        S3 Virge  (and variants VX, DX, GX and GX2+)
+        S3 Plato/PX             (completely untested)
+        S3 Aurora64V+           (completely untested)
+
+        - only PCI bus supported
+        - only BIOS initialized VGA devices supported
+        - probably not working on big endian
+
+I tested s3fb on Trio64 (plain, V+ and V2/DX) and Virge (plain, VX, DX),
+all on i386.
+
+
+Supported Features
+==================
+
+        *  4 bpp pseudocolor modes (with 18bit palette, two variants)
+        *  8 bpp pseudocolor mode (with 18bit palette)
+        * 16 bpp truecolor modes (RGB 555 and RGB 565)
+        * 24 bpp truecolor mode (RGB 888) on (only on Virge VX)
+        * 32 bpp truecolor mode (RGB 888) on (not on Virge VX)
+        * text mode (activated by bpp = 0)
+        * interlaced mode variant (not available in text mode)
+        * 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 between 50-60 MHz, depending on specific hardware).
+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
+        * big endian support
+        * Zorro bus support
+        * MMIO support
+        * 24 bpp mode support on more cards
+        * support for fontwidths != 8 in 4 bpp modes
+        * support for fontheight != 16 in text mode
+        * composite and external sync (is anyone able to test this?)
+        * hardware cursor
+        * video overlay support
+        * vsync synchronization
+        * feature connector support
+        * acceleration support (8514-like 2D, Virge 3D, busmaster transfers)
+        * better values for some magic registers (performance issues)
+
+
+Known bugs
+==========
+
+        * cursor disable in text mode doesn't work
+
+--
+Ondrej Zajicek <santiago@crfreenet.org>