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Indice(depth=2) Informazioni(forum="http://forum.ubuntu-it.org/"; rilasci="10.04")

Titolo: informazioni per scheda sis 6326:

Versioni Supportate: Lubuntu 10.04

Riferimenti

http://www.winischhofer.net/linuxsisvga.shtml

Video overlay method

Hardware video acceleration ("Xv") is primarily done through a so-called "overlay" window provided by the graphics hardware. 
...
The maximum video frame size (size of video source) is

384x288 on the 5597/5598,
720x576 on the 6326, 530/620,

X driver:       UseSSE
Parameter:      boolean
Chipsets:       all
Description:     One of the X driver's memory transfer methods makes use of SSE instructions on x86 (ia-32) and AMD64, if supported by the CPU. However, while the CPU might support SSE, the OS needs to specifically support it, too. Unfortunately, the X server does not allow checking operating system support for SSE; therefore, using SSE instructions is disabled by default. To enable it, set this option to "on".

Linux (2.4, 2.6) and *BSD generally support SSE (if the kernel is compiled for the correct CPU), so it's save to set this option to "on". If you get a "signal 4" during X server start, set this option to "off".

(X.org 6.9.0 will support automatic detection, rendering this option redundant.)

Synopsis/Example:
        
Option "UseSSE" "yes"

Q: Xv is terribly slow and takes 30% CPU time or more. What's wrong?
A: As of 06/05/2003, there is a confirmed bug in the SuSE 8.2 XFree 4.3 packages and probably in XFree 4.3 packages of some other distributions as well. This is no SiS driver bug and there is no real workaround available. However, on some systems, especially Athlon based ones, it helps setting the option XvUseMemcpy to false. Later versions of XFree86 will hopefully fix this problem rendering this option unneccessary. (Technical explanation: There is a problem with memory access in these versions of XFree86, rendering memcpy-operations to video RAM extremely slow. SiS hardware is not the only one affected, there were numerous complaints from users of other hardware, too. This bug is also known as the "O_SYNC bug". If you want to know more, search the archive of the xdevel mailing list for a thread named "Athlon related mystery".)
 
Q: Xv video playback, and especially DVD playback, is terribly slow and I have read the above answer. Any further hints?
A: Yes, two in fact. First, check that MTRR is enabled in your kernel. This is important as it severely speeds up memory-to-memory data transfers. Check your X log for lines like "Failed to set up write-combining range" followed by hex numbers. If you find such lines, your kernel lacks MTRR support. Solution: Reconfigure and reinstall your kernel. Furthermore, for DVD playback, it is essential to have DMA enabled for the data transfer from the DVD drive to memory. To find out, open a console as root, and type hdparm /dev/hdc where /dev/hdc is the device file for your DVD drive. This might vary. However, if hdparm says "using_dma = 0", DMA is not enabled. In this case, try hdparm -d /dev/hdc. If this fails, check your kernel configuration. Under the IDE/ATA options, there is one to enable DMA transfers. Make sure this option is set

http://gd.tuwien.ac.at/hci/x.org/X11R7.0/doc/html/SiS2.html (xorg.conf)

Among other features, the driver supports
8/16/24 bits color depth; old series also 15
XAA; EXA; XVideo (Xv); RENDER and other extensions

In the list below, the options' arguments are described by type. For "boolean", the keywords "on", "true" and "yes", as well as "off", "false" and "no" respectively have the same meaning.

Option "AccelMethod" string]
Determines which acceleration architecture should be used. Possible arguments are "XAA" or "EXA". As of this writing, EXA is still experimental and it is not recommended to be used on production machines. By default, XAA will be used.

https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-sis/+bug/380413

man sis:

       Option "FastVram" "boolean"
              Enable or disable FastVram mode.  Enabling this sets  the  video
              RAM  timing  to  one  cycle  per  read  operation instead of two
              cycles. Disabling this will set two cycles for  read  and  write
              operations.  Leaving  this  option  out  uses the default, which
              varies depending on the chipset.
       Option "NoYV12" "boolean"
              Disable YV12 Xv support. This might me required due to  hardware
              bugs  in  some  chipsets. Disabling YV12 support forces Xv-aware
              applications to use YUV2 or XShm  for  video  output.   Default:
              YV12 support is on.

Xorg.0.log:

(II) SIS(0): VESA VBE Total Mem: 4096 kB
(II) SIS(0): 2D acceleration enabled

(II) SIS(0): Checking OS for SSE support is not supported in this version of X.org
(II) SIS(0): If your OS supports SSE, set the option "UseSSE" to "on".


(II) SIS(0): Using XFree86 Acceleration Architecture (XAA)
        Screen to screen bit blits
        Solid filled rectangles
        Solid Horizontal and Vertical Lines
        Setting up tile and stipple cache:
                10 128x50 slots

(--) SIS(0): CPU frequency 637.57Mhz
(II) SIS(0): Failed to allocate video RAM for video data transfer benchmark
(II) SIS(0): Chose MMX2 method for aligned data transfers to video RAM
(II) SIS(0): Chose MMX2 method for unaligned data transfers to video RAM
(==) SIS(0): Backing store disabled
(==) SIS(0): Silken mouse enabled
(==) SIS(0): DPMS enabled
(II) SIS(0): Using SiS5597/5598/6326/530/620 HW Xv
(II) AIGLX: Screen 0 is not DRI2 capable
(II) AIGLX: Screen 0 is not DRI capable
(II) AIGLX: Loaded and initialized /usr/lib/dri/swrast_dri.so
(II) GLX: Initialized DRISWRAST GL provider for screen 0

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