mirror of https://gitee.com/openkylin/linux.git
69 lines
2.0 KiB
ReStructuredText
69 lines
2.0 KiB
ReStructuredText
========================================
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arkfb - fbdev driver for ARK Logic chips
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========================================
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Supported Hardware
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==================
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ARK 2000PV chip
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ICS 5342 ramdac
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- only BIOS initialized VGA devices supported
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- probably not working on big endian
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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 modes (RGB 555 and RGB 565)
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* 24 bpp truecolor mode (RGB 888)
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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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Text mode is supported even in higher resolutions, but there is limitation to
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lower pixclocks (i got maximum about 70 MHz, it is dependent on specific
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hardware). This limitation is not enforced by driver. Text mode supports 8bit
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wide fonts only (hardware limitation) and 16bit tall fonts (driver
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limitation). Unfortunately character attributes (like color) in text mode are
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broken for unknown reason, so its usefulness is limited.
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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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* big endian support
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* DPMS 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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* vsync synchronization
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* feature connector support
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* acceleration support (8514-like 2D)
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Known bugs
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==========
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* character attributes (and cursor) in text mode are broken
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--
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Ondrej Zajicek <santiago@crfreenet.org>
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