framebuffer: new driver for cyberblade/i1 core

diff -urN linux-2.6.13-rc4/Documentation/fb/cyblafb.txt linux-2.6.13-rc4-tfix/Documentation/fb/cyblafb.txt
@@ -0,0 +1,354 @@
+CyBlaFB is a framebuffer driver for the Cyberblade/i1 graphics core integrated
+into the VIA Apollo PLE133 (aka vt8601) south bridge. It is developed and
+tested using a VIA EPIA 5000 board.
+
+
+Why CyBlaFB?
+============
+
+I tried the following framebuffer drivers:
+
+	- TRIDENTFB is full of bugs. Acceleration is broken for Blade3D
+	  graphics cores like the cyberblade/i1. It claims to support a great
+	  number of devices, but documentation for most of these devices is
+	  unfortunately not available. There is _no_ reason to use tridentfb
+	  for cyberblade/i1 + CRT users. VESAFB is faster, and the one
+	  advantage, mode switching, is broken in tridentfb.
+
+	- VESAFB is used by many distributions as a standard. Vesafb does
+	  not support mode switching. VESAFB is a bit faster than the working
+	  configurations of TRIDENTFB, but it is still too slow, even if you
+	  use ypan.
+
+	- EPIAFB (you'll find it on sourceforge) supports the Cyberblade/i1
+	  graphics core, but it still has serious bugs and developement seems
+	  to have stopped. This is the one driver with TV-out support. If you
+	  do need this feature, use epiafb.
+
+None of these drivers was a real option for me.
+
+I believe that is unreasonable to change code that announces to support 20
+devices if I only have more or less sufficient documentation for exactly one
+of these. The risk of breaking device foo while fixing device bar is too high.
+
+So I decided to start CyBlaFB as a stripped down tridentfb.
+
+All code specific to other Trident chips has been removed. After that there
+were a lot of cosmetic changes to increase the readability of the code. All
+register names were changed to those mnemonics used in the datasheet. Function
+and macro names were changed if they hindered easy understanding of the code.
+
+After that I debugged the code and implemented some new features. I'll try to
+give a little summary of the main changes:
+
+	- calculation of vertical and horizontal timings was fixed
+
+	- video signal quality has been improved dramatically
+
+	- acceleration:
+
+		- fillrect and copyarea were fixed and reenabled
+
+		- color expanding imageblit was newly implemented, color
+		  imageblit (only used to draw the penguine) still uses the
+		  generic code.
+
+		- init of the acceleration engine was improved and moved to a
+		  place where it really works ...
+
+		- sync function has a timeout now and tries to reset and
+		  reinit the accel engine if necessary
+
+		- fewer slow copyarea calls when doing ypan scrolling by using
+		  undocumented bit d21 of screen start address stored in
+		  CR2B[5]. BIOS does use it also, so this should be safe.
+
+	- cyblafb rejects any attempt to set modes that would cause vclk
+	  values above reasonable 230 MHz. 32bit modes use a clock
+	  multiplicator of 2, so fbset does show the correct values for
+	  pixclock but not for vclk in this case. The fbset limit is 115 MHz
+	  for 32 bpp modes.
+
+	- cyblafb rejects modes known to be broken or unimplemented (all
+	  interlaced modes, all doublescan modes for now)
+
+	- cyblafb now works independant of the video mode in effect at startup
+	  time (tridentfb does not init all needed registers to reasonable
+	  values)
+
+	- switching between video modes does work reliably now
+
+	- the first video mode now is the one selected on startup using the
+	  vga=???? mechanism or any of
+		- 640x480, 800x600, 1024x768, 1280x1024
+		- 8, 16, 24 or 32 bpp
+		- refresh between 50 Hz and 85 Hz, 1 Hz steps (1280x1024-32
+		  is limited to 63Hz)
+
+	- pci retry and pci burst mode are settable (try to disable if you
+	  experience latency problems)
+
+	- built as a module cyblafb might be unloaded and reloaded using
+	  the vfb module and con2vt or might be used together with vesafb
+
+Speed
+=====
+
+CyBlaFB is much faster than tridentfb and vesafb. Compare the performance data
+for mode 1280x1024-[8,16,32]@61 Hz.
+
+Test 1: Cat a file with 2000 lines of 0 characters.
+Test 2: Cat a file with 2000 lines of 80 characters.
+Test 3: Cat a file with 2000 lines of 160 characters.
+
+All values show system time use in seconds, kernel 2.6.12 was used for
+the measurements. 2.6.13-rc4 is much slower, but this problem has been
+solved, and 2.6.13 should be actually faster than 2.6.12.
+
++-----------+-----------------------------------------------------+
+|	    |			not accelerated 		  |
+| TRIDENTFB +-----------------+-----------------+-----------------+
+| of 2.6.12 |	   8 bpp      |     16 bpp	|     32 bpp	  |
+|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
++-----------+--------+--------+--------+--------+--------+--------+
+|    Test 1 |	4.31 |	 4.33 |   6.05 |  12.81 |  ----  |  ----  |
+|    Test 2 |  67.94 |	 5.44 | 123.16 |  14.79 |  ----  |  ----  |
+|    Test 3 | 131.36 |	 6.55 | 240.12 |  16.76 |  ----  |  ----  |
++-----------+--------+--------+--------+--------+--------+--------+
+|  Comments |		      | 		| completely bro- |
+|	    |		      | 		| ken, monitor	  |
+|	    |		      | 		| switches off	  |
++-----------+-----------------+-----------------+-----------------+
+
+
++-----------+-----------------------------------------------------+
+|	    |			  accelerated			  |
+| TRIDENTFB +-----------------+-----------------+-----------------+
+| of 2.6.12 |	   8 bpp      |     16 bpp	|     32 bpp	  |
+|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
++-----------+--------+--------+--------+--------+--------+--------+
+|    Test 1 |  ----  |	----  |  20.62 |   1.22 |  ----  |  ----  |
+|    Test 2 |  ----  |	----  |  22.61 |   3.19 |  ----  |  ----  |
+|    Test 3 |  ----  |	----  |  24.59 |   5.16 |  ----  |  ----  |
++-----------+--------+--------+--------+--------+--------+--------+
+|  Comments | broken, writing | broken, ok only | completely bro- |
+|	    | to wrong places | if bgcolor is	| ken, monitor	  |
+|	    | on screen + bug | black, bug in	| switches off	  |
+|	    | in fillrect()   | fillrect()	|		  |
++-----------+-----------------+-----------------+-----------------+
+
+
++-----------+-----------------------------------------------------+
+|	    |			not accelerated 		  |
+|   VESAFB  +-----------------+-----------------+-----------------+
+| of 2.6.12 |	   8 bpp      |     16 bpp	|     32 bpp	  |
+|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
++-----------+--------+--------+--------+--------+--------+--------+
+|    Test 1 |	4.26 |	 3.76 |   5.99 |   7.23 |  ----  |  ----  |
+|    Test 2 |  65.65 |	 4.89 | 120.88 |   9.08 |  ----  |  ----  |
+|    Test 3 | 126.91 |	 5.94 | 235.77 |  11.03 |  ----  |  ----  |
++-----------+--------+--------+--------+--------+--------+--------+
+|  Comments | vga=0x307       | vga=0x31a	| vga=0x31b not   |
+|	    | fh=80kHz	      | fh=80kHz	| supported by	  |
+|	    | fv=75kHz	      | fv=75kHz	| video BIOS and  |
+|	    |		      | 		| hardware	  |
++-----------+-----------------+-----------------+-----------------+
+
+
++-----------+-----------------------------------------------------+
+|	    |			  accelerated			  |
+|  CYBLAFB  +-----------------+-----------------+-----------------+
+|	    |	   8 bpp      |     16 bpp	|     32 bpp	  |
+|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
++-----------+--------+--------+--------+--------+--------+--------+
+|    Test 1 |	8.02 |	 0.23 |  19.04 |   0.61 |  57.12 |   2.74 |
+|    Test 2 |	8.38 |	 0.55 |  19.39 |   0.92 |  57.54 |   3.13 |
+|    Test 3 |	8.73 |	 0.86 |  19.74 |   1.24 |  57.95 |   3.51 |
++-----------+--------+--------+--------+--------+--------+--------+
+|  Comments |		      | 		|		  |
+|	    |		      | 		|		  |
+|	    |		      | 		|		  |
+|	    |		      | 		|		  |
++-----------+-----------------+-----------------+-----------------+
+
+Startup Mode
+============
+
+Tridentfb uses modedb.c to allow the user to specify a startup video mode.
+Unfortunately a lot of the video mode specifyed there do not display
+correctly, including the default video mode. My first idea was to implement
+some code in check_var() to alter these modes to values acceptable for the
+graphics core. I wrote some code, but I dumped it completely. If you tweak the
+modes, you need to provide at least kernel parameters to disable those
+helpers. If you don't want to force the user to reboot in those cases you have
+to provide some ioctls and a special control program as fbset etc do not know
+about the new ioctls. No, this is not the perfect solution. But we already
+have a video mode selection mechanism in the kernel. Why shouldn't we use
+vga=xxx to select an initial video mode? This way we get a reasonable
+collection of startup modes (every mode the bios supports) and those people
+who really need to use fbset are not hindered by some magic in check_var()
+that alters the parameters they provide. You might also specify an inital
+video mode, see section "parameters"
+
+
+Untested features
+=================
+
+All LCD stuff is untested. If it worked in tridentfb, it should work in
+cyblafb. Please test and report the results
+
+
+known BUGS
+==========
+
+I don't know of any bug, but please do send reports to both LKML and
[email protected].
+
+
+TODO / Missing features
+=======================
+
+Interlaced video modes		The reason that interleaved
+				modes are disabled is that I do not know
+				the meaning of the vertical interlace
+				parameter. Also the datasheet mentions a
+				bit d8 of a horizontal interlace parameter,
+				but nowhere the lower 8 bits. Please help
+				if you can.
+
+low-res double scan modes	Who needs it?
+
+accelerated color blitting	Who needs it? The console driver does use color
+				blitting for nothing but drawing the penguine,
+				everything else is done using color expanding
+				blitting of 1bpp character bitmaps.
+
+xpanning			Who needs it?
+
+ioctls				Who needs it?
+
+TV-out				Will be done later
+
+
+Available Documentation
+=======================
+
+Apollo PLE 133 Chipset VT8601A North Bridge Datasheet, Rev. 1.82, October 22,
+2001, available from VIA. The datasheet is incomplete, some registers that
+need to be programmed are not explained at all or important bits are listed
+as "reserved". But you really need the datasheet to understand the code.
+"p. xxx comments refer to page numbers of this document."
+
+XFree/XOrg drivers are available and of good quality, looking at the code
+there is a good idea if the documentation does not provide enough information
+or if the documentation seems to be wrong.
+
+Parameters
+==========
+
+
+crt		don't autodetect, assume monitor connected to
+		standard VGA connector
+
+fp		don't autodetect, assume flat panel display
+		connected to flat panel monitor interface
+
+nativex 	inform driver about native x resolution of
+		flat panel monitor connected to special
+		interface
+
+stretch 	stretch image to adapt low resolution modes to
+		higer resolutions of flat panel monitors
+		connected to special interface
+
+center		center image to adapt low resolution modes to
+		higer resolutions of flat panel monitors
+		connected to special interface
+
+memsize 	use if autodetected memsize is wrong ...
+		should never be necessary
+
+nopcirr 	disable PCI read retry
+nopciwr 	disable PCI write retry
+nopcirb 	disable PCI read bursts
+nopciwb 	disable PCI write bursts
+
+regdumps	This will print a listing of the contents of
+		most registers to syslog immediately after startup
+		and after a new mode is set. Please do include if
+		you send a bugreport
+
+bpp		bpp for specified modes
+
+ref		refresh rate for specified mode
+
+mode		640x480 or 800x600 or 1024x768 or 1280x1024
+		if not specified, the startup mode will be detected
+		and used, so you might also use the vga=??? parameter
+		described in vesafb.txt. If you do not specify a mode,
+		bpp and ref parameters are ignored.
+
+verbosity	0 is the default, increase to at least 2 for every
+		bug report!
+
+vesafb		allows cyblafb to be loaded after vesafb has been
+		loaded. See sections "Module unloading ...".
+
+Module unloading, the vfb method
+================================
+
+If you want to unload/reload cyblafb, you need to enable vfb support in the
+kernel first. After that, load the modules as shown below:
+
+	modprobe vfb vfb_enable=1
+	modprobe fbcon
+	modprobe cyblafb
+	fbset -fb /dev/fb1 1280x1024-60 -vyres 2662
+	con2fb /dev/fb1 /dev/tty1
+	...
+
+If you now made some changes to cyblafb and want to reload it, you might do it
+as show below:
+
+	con2fb /dev/fb0 /dev/tty1
+	...
+	rmmod cyblafb
+	modprobe cyblafb
+	con2fb /dev/fb1 /dev/tty1
+	...
+
+Of course, you might choose another mode, and most certainly you also want to
+map some other /dev/tty* to the real framebuffer device. You might also choose
+to compile fbcon as a kernel module or place it permanently in the kernel.
+
+I do not know of any way to unload fbcon, and fbcon will prevent the
+framebuffer device loaded first from unloading. [If there is a way, then
+please add a description here!]
+
+Module unloading, the vesafb method
+===================================
+
+Configure the kernel:
+
+	<*> Support for frame buffer devices
+	[*]   VESA VGA graphics support
+	<M>   Cyberblade/i1 support
+
+Add e.g. "video=vesafb:ypan vga=0x307" to the kernel parameters. The ypan
+parameter is important, choose any vga parameter you like as long as it is
+a graphics mode.
+
+After booting, load cyblafb without any mode and bpp parameter and assign
+cyblafb to individual ttys using con2fb, e.g.:
+
+	modprobe cyblafb vesafb=1
+	con2fb /dev/fb1 /dev/tty1
+
+Unloading cyblafb works without problems after you assign vesafb to all
+ttys again, e.g.:
+
+	con2fb /dev/fb0 /dev/tty1
+	rmmod cyblafb
+
+
+

diff -urN linux-2.6.13-rc4/MAINTAINERS linux-2.6.13-rc4-tfix/MAINTAINERS
@@ -627,6 +627,12 @@

diff -urN linux-2.6.13-rc4/drivers/video/Kconfig linux-2.6.13-rc4-tfix/drivers/video/Kconfig
@@ -1180,6 +1180,32 @@

diff -urN linux-2.6.13-rc4/drivers/video/Makefile linux-2.6.13-rc4-tfix/drivers/video/Makefile
@@ -50,7 +50,8 @@