projects / mirror_ubuntu-bionic-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 558b7bd8 OZ |
1 | |
| 2 | vt8623fb - fbdev driver for graphics core in VIA VT8623 chipset | |
| 3 | =============================================================== | |
| 4 | ||
| 5 | ||
| 6 | Supported Hardware | |
| 7 | ================== | |
| 8 | ||
| 9 | VIA VT8623 [CLE266] chipset and its graphics core | |
| 10 | (known as CastleRock or Unichrome) | |
| 11 | ||
| 12 | I tested vt8623fb on VIA EPIA ML-6000 | |
| 13 | ||
| 14 | ||
| 15 | Supported Features | |
| 16 | ================== | |
| 17 | ||
| 18 | * 4 bpp pseudocolor modes (with 18bit palette, two variants) | |
| 19 | * 8 bpp pseudocolor mode (with 18bit palette) | |
| 20 | * 16 bpp truecolor mode (RGB 565) | |
| 21 | * 32 bpp truecolor mode (RGB 888) | |
| 22 | * text mode (activated by bpp = 0) | |
| 23 | * doublescan mode variant (not available in text mode) | |
| 24 | * panning in both directions | |
| 25 | * suspend/resume support | |
| 26 | * DPMS support | |
| 27 | ||
| 28 | Text mode is supported even in higher resolutions, but there is limitation to | |
| 29 | lower pixclocks (maximum about 100 MHz). This limitation is not enforced by | |
| 30 | driver. Text mode supports 8bit wide fonts only (hardware limitation) and | |
| 31 | 16bit tall fonts (driver limitation). | |
| 32 | ||
| 33 | There are two 4 bpp modes. First mode (selected if nonstd == 0) is mode with | |
| 34 | packed pixels, high nibble first. Second mode (selected if nonstd == 1) is mode | |
| 35 | with interleaved planes (1 byte interleave), MSB first. Both modes support | |
| 36 | 8bit wide fonts only (driver limitation). | |
| 37 | ||
| 38 | Suspend/resume works on systems that initialize video card during resume and | |
| 39 | if device is active (for example used by fbcon). | |
| 40 | ||
| 41 | ||
| 42 | Missing Features | |
| 43 | ================ | |
| 44 | (alias TODO list) | |
| 45 | ||
| 46 | * secondary (not initialized by BIOS) device support | |
| 47 | * MMIO support | |
| 48 | * interlaced mode variant | |
| 49 | * support for fontwidths != 8 in 4 bpp modes | |
| 50 | * support for fontheight != 16 in text mode | |
| 51 | * hardware cursor | |
| 52 | * video overlay support | |
| 53 | * vsync synchronization | |
| 54 | * acceleration support (8514-like 2D, busmaster transfers) | |
| 55 | ||
| 56 | ||
| 57 | Known bugs | |
| 58 | ========== | |
| 59 | ||
| 60 | * cursor disable in text mode doesn't work | |
| 61 | ||
| 62 | ||
| 63 | -- | |
| 64 | Ondrej Zajicek <santiago@crfreenet.org> |