[linux-dvb] probably driver bug...

[<mocm@metzlerbros.de>]

Guido Fiala writes:
 > Recently i mentioned that since kvdr can do Xv me and other people observe 
 > short horizontal green or pink lines at the display (color space conversion 
 > might affect actual color).
 > 
 > To track that down to a certain component i tried the following combinations:
 > 
 > -Xv on dvb "playing" - above glitches <#########
 > -grabbing images on a playing dvb - occasional glitches <#########
 > -Xv on dvb "live" - no glitches
 > -Xv on dvb "recording" - no glitches
 > -Xv on primary dvb while secondary recording - no glitches
 > -Xv on secondary while primary playing - no glitches
 > -Xv on analog WinTV feeded with the output of a playing dvb - no glitches
 > -grabbing images on recording, live dvb - no idea if or if not 
 > (can someone verify?)
 > -disk activity in general as mentioned earlier is not the problem!
 > 
 > Conclusion:
 > There seems to go something wrong in the dvb-driver with the mem-map'ed IO 
 > during grabbing, probably reading that memory addresses returns all zero's 
 > for that part of the image. It is a short term problem - just one frame - 
 > occuring more or less distributed over the entire screen and very annoying :-(
 > 
 > Is there any hope to fix that in the dvb-driver or is it a firmware related 
 > problem?
 > 

Those glitches don't seem to be errors in the MPEG stream, which
usually look more like blocks. It could be a problem with PCI latency,
although that usually shows up all the time. If the TV out shows a
correct picture it has something to do with the DMA into video memory,
which is not influenced by the firmware. 
What kind of chipset does your board have ?
What graphics card?
Is it limited to the screen resolution, or maybe size of the picture?
Is it present when not using Xv, e.g, with tuxview?
Is it limited to one type graphics card?

Marcus

-- 
/--------------------------------------------------------------------\
| Dr. Marcus O.C. Metzler        |                                   |
|--------------------------------|-----------------------------------|
| mocm@metzlerbros.de            | http://www.metzlerbros.de/        |
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