65 lines
1.9 KiB
ReStructuredText
65 lines
1.9 KiB
ReStructuredText
===============================================================
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vt8623fb - fbdev driver for graphics core in VIA VT8623 chipset
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===============================================================
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Supported Hardware
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==================
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VIA VT8623 [CLE266] chipset and its graphics core
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(known as CastleRock or Unichrome)
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I tested vt8623fb on VIA EPIA ML-6000
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Supported Features
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==================
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* 4 bpp pseudocolor modes (with 18bit palette, two variants)
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* 8 bpp pseudocolor mode (with 18bit palette)
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* 16 bpp truecolor mode (RGB 565)
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* 32 bpp truecolor mode (RGB 888)
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* text mode (activated by bpp = 0)
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* doublescan mode variant (not available in text mode)
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* panning in both directions
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* suspend/resume support
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* DPMS support
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Text mode is supported even in higher resolutions, but there is limitation to
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lower pixclocks (maximum about 100 MHz). This limitation is not enforced by
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driver. Text mode supports 8bit wide fonts only (hardware limitation) and
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16bit tall fonts (driver limitation).
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There are two 4 bpp modes. First mode (selected if nonstd == 0) is mode with
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packed pixels, high nibble first. Second mode (selected if nonstd == 1) is mode
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with interleaved planes (1 byte interleave), MSB first. Both modes support
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8bit wide fonts only (driver limitation).
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Suspend/resume works on systems that initialize video card during resume and
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if device is active (for example used by fbcon).
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Missing Features
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================
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(alias TODO list)
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* secondary (not initialized by BIOS) device support
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* MMIO support
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* interlaced mode variant
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* support for fontwidths != 8 in 4 bpp modes
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* support for fontheight != 16 in text mode
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* hardware cursor
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* video overlay support
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* vsync synchronization
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* acceleration support (8514-like 2D, busmaster transfers)
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Known bugs
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==========
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* cursor disable in text mode doesn't work
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--
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Ondrej Zajicek <santiago@crfreenet.org>
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