diff options
Diffstat (limited to 'Documentation/fb')
| -rw-r--r-- | Documentation/fb/arkfb.txt | 68 | ||||
| -rw-r--r-- | Documentation/fb/aty128fb.txt | 4 | ||||
| -rw-r--r-- | Documentation/fb/deferred_io.txt | 75 | ||||
| -rw-r--r-- | Documentation/fb/framebuffer.txt | 16 | ||||
| -rw-r--r-- | Documentation/fb/imacfb.txt | 2 | ||||
| -rw-r--r-- | Documentation/fb/s3fb.txt | 12 | ||||
| -rw-r--r-- | Documentation/fb/sstfb.txt | 4 | ||||
| -rw-r--r-- | Documentation/fb/vt8623fb.txt | 64 |
8 files changed, 228 insertions, 17 deletions
diff --git a/Documentation/fb/arkfb.txt b/Documentation/fb/arkfb.txt new file mode 100644 index 000000000000..e8487a9d6a05 --- /dev/null +++ b/Documentation/fb/arkfb.txt @@ -0,0 +1,68 @@ + + arkfb - fbdev driver for ARK Logic chips + ======================================== + + +Supported Hardware +================== + + ARK 2000PV chip + ICS 5342 ramdac + + - only BIOS initialized VGA devices supported + - probably not working on big endian + + +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) + * 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 + +Text mode is supported even in higher resolutions, but there is limitation to +lower pixclocks (i got maximum about 70 MHz, it is dependent 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). Unfortunately character attributes (like color) in text mode are +broken for unknown reason, so its usefulness is limited. + +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 + * DPMS support + * MMIO support + * interlaced mode variant + * support for fontwidths != 8 in 4 bpp modes + * support for fontheight != 16 in text mode + * hardware cursor + * vsync synchronization + * feature connector support + * acceleration support (8514-like 2D) + + +Known bugs +========== + + * character attributes (and cursor) in text mode are broken + +-- +Ondrej Zajicek <santiago@crfreenet.org> diff --git a/Documentation/fb/aty128fb.txt b/Documentation/fb/aty128fb.txt index 069262fb619d..b605204fcfe1 100644 --- a/Documentation/fb/aty128fb.txt +++ b/Documentation/fb/aty128fb.txt @@ -54,8 +54,8 @@ Accepted options: noaccel - do not use acceleration engine. It is default. accel - use acceleration engine. Not finished. -vmode:x - chooses PowerMacintosh video mode <x>. Depreciated. -cmode:x - chooses PowerMacintosh colour mode <x>. Depreciated. +vmode:x - chooses PowerMacintosh video mode <x>. Deprecated. +cmode:x - chooses PowerMacintosh colour mode <x>. Deprecated. <XxX@X> - selects startup videomode. See modedb.txt for detailed explanation. Default is 640x480x8bpp. diff --git a/Documentation/fb/deferred_io.txt b/Documentation/fb/deferred_io.txt new file mode 100644 index 000000000000..73cf9fb7cf60 --- /dev/null +++ b/Documentation/fb/deferred_io.txt @@ -0,0 +1,75 @@ +Deferred IO +----------- + +Deferred IO is a way to delay and repurpose IO. It uses host memory as a +buffer and the MMU pagefault as a pretrigger for when to perform the device +IO. The following example may be a useful explaination of how one such setup +works: + +- userspace app like Xfbdev mmaps framebuffer +- deferred IO and driver sets up nopage and page_mkwrite handlers +- userspace app tries to write to mmaped vaddress +- we get pagefault and reach nopage handler +- nopage handler finds and returns physical page +- we get page_mkwrite where we add this page to a list +- schedule a workqueue task to be run after a delay +- app continues writing to that page with no additional cost. this is + the key benefit. +- the workqueue task comes in and mkcleans the pages on the list, then + completes the work associated with updating the framebuffer. this is + the real work talking to the device. +- app tries to write to the address (that has now been mkcleaned) +- get pagefault and the above sequence occurs again + +As can be seen from above, one benefit is roughly to allow bursty framebuffer +writes to occur at minimum cost. Then after some time when hopefully things +have gone quiet, we go and really update the framebuffer which would be +a relatively more expensive operation. + +For some types of nonvolatile high latency displays, the desired image is +the final image rather than the intermediate stages which is why it's okay +to not update for each write that is occuring. + +It may be the case that this is useful in other scenarios as well. Paul Mundt +has mentioned a case where it is beneficial to use the page count to decide +whether to coalesce and issue SG DMA or to do memory bursts. + +Another one may be if one has a device framebuffer that is in an usual format, +say diagonally shifting RGB, this may then be a mechanism for you to allow +apps to pretend to have a normal framebuffer but reswizzle for the device +framebuffer at vsync time based on the touched pagelist. + +How to use it: (for applications) +--------------------------------- +No changes needed. mmap the framebuffer like normal and just use it. + +How to use it: (for fbdev drivers) +---------------------------------- +The following example may be helpful. + +1. Setup your structure. Eg: + +static struct fb_deferred_io hecubafb_defio = { + .delay = HZ, + .deferred_io = hecubafb_dpy_deferred_io, +}; + +The delay is the minimum delay between when the page_mkwrite trigger occurs +and when the deferred_io callback is called. The deferred_io callback is +explained below. + +2. Setup your deferred IO callback. Eg: +static void hecubafb_dpy_deferred_io(struct fb_info *info, + struct list_head *pagelist) + +The deferred_io callback is where you would perform all your IO to the display +device. You receive the pagelist which is the list of pages that were written +to during the delay. You must not modify this list. This callback is called +from a workqueue. + +3. Call init + info->fbdefio = &hecubafb_defio; + fb_deferred_io_init(info); + +4. Call cleanup + fb_deferred_io_cleanup(info); diff --git a/Documentation/fb/framebuffer.txt b/Documentation/fb/framebuffer.txt index 610e7801207b..b3e3a0356839 100644 --- a/Documentation/fb/framebuffer.txt +++ b/Documentation/fb/framebuffer.txt @@ -215,11 +215,11 @@ vertical retrace time is the sum of the upper margin, the lower margin and the vsync length. +----------+---------------------------------------------+----------+-------+ - | | ^ | | | + | | ↑ | | | | | |upper_margin | | | - | | ¥ | | | + | | ↓ | | | +----------###############################################----------+-------+ - | # ^ # | | + | # ↑ # | | | # | # | | | # | # | | | # | # | | @@ -238,15 +238,15 @@ vsync length. | # | # | | | # | # | | | # | # | | - | # ¥ # | | + | # ↓ # | | +----------###############################################----------+-------+ - | | ^ | | | + | | ↑ | | | | | |lower_margin | | | - | | ¥ | | | + | | ↓ | | | +----------+---------------------------------------------+----------+-------+ - | | ^ | | | + | | ↑ | | | | | |vsync_len | | | - | | ¥ | | | + | | ↓ | | | +----------+---------------------------------------------+----------+-------+ The frame buffer device expects all horizontal timings in number of dotclocks diff --git a/Documentation/fb/imacfb.txt b/Documentation/fb/imacfb.txt index 759028545a7e..316ec9bb7deb 100644 --- a/Documentation/fb/imacfb.txt +++ b/Documentation/fb/imacfb.txt @@ -17,7 +17,7 @@ How to use it? ============== Imacfb does not have any kind of autodetection of your machine. -You have to add the fillowing kernel parameters in your elilo.conf: +You have to add the following kernel parameters in your elilo.conf: Macbook : video=imacfb:macbook MacMini : diff --git a/Documentation/fb/s3fb.txt b/Documentation/fb/s3fb.txt index 8a04c0da0c91..2c97770bdbaa 100644 --- a/Documentation/fb/s3fb.txt +++ b/Documentation/fb/s3fb.txt @@ -35,10 +35,12 @@ Supported Features * 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). +Text mode is supported even in higher resolutions, but there is limitation to +lower pixclocks (maximum usually between 50-60 MHz, depending on specific +hardware, i get best results from plain S3 Trio32 card - about 75 MHz). This +limitation is not enforced by driver. Text mode supports 8bit wide fonts only +(hardware limitation) and 16bit tall fonts (driver limitation). Text mode +support is broken on S3 Trio64 V2/DX. 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 @@ -73,6 +75,8 @@ Known bugs ========== * cursor disable in text mode doesn't work + * text mode broken on S3 Trio64 V2/DX + -- Ondrej Zajicek <santiago@crfreenet.org> diff --git a/Documentation/fb/sstfb.txt b/Documentation/fb/sstfb.txt index df27f5bf15db..550ca775a4cb 100644 --- a/Documentation/fb/sstfb.txt +++ b/Documentation/fb/sstfb.txt @@ -2,9 +2,9 @@ Introduction This is a frame buffer device driver for 3dfx' Voodoo Graphics - (aka voodoo 1, aka sst1) and Voodoo² (aka Voodoo 2, aka CVG) based + (aka voodoo 1, aka sst1) and Voodoo² (aka Voodoo 2, aka CVG) based video boards. It's highly experimental code, but is guaranteed to work - on my computer, with my "Maxi Gamer 3D" and "Maxi Gamer 3d²" boards, + on my computer, with my "Maxi Gamer 3D" and "Maxi Gamer 3d²" boards, and with me "between chair and keyboard". Some people tested other combinations and it seems that it works. The main page is located at <http://sstfb.sourceforge.net>, and if diff --git a/Documentation/fb/vt8623fb.txt b/Documentation/fb/vt8623fb.txt new file mode 100644 index 000000000000..f654576c56b7 --- /dev/null +++ b/Documentation/fb/vt8623fb.txt @@ -0,0 +1,64 @@ + + 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> |