Mauro Carvalho Chehab wrote: > Alan, > Em Seg, 2006-03-20 às 23:09 +0100, thomas schorpp escreveu: > >>Alan Stern wrote: >> >>>On Wed, 15 Mar 2006, Ballentine, Casey wrote: > > >>what DMA problem? ive always used via chipsets with usb. now the 8237. > > >>the via pci-busmaster dma hangs the system? > > No. it is PCI to PCI transfers ocurring while you have DMA transfers.
i see > > Video capture boards allow you to transfer information from his capture > memory to video memory without CPU. classic vga video overlay, e.g., right? > The problem is that some chipsets > (or BIOS) can't handle concurrency between such transfers and normal PCI > busmaster transfers. maybe the reason for the green flashes in the picture i have with epox 8kha+ and asrock k7vt4a+ (both via 82xx). its gone since i added a sil680 pci ide-controller for the disks and using the via ide only for dvdr/dvdrw drives now.. > >> try setting pci latency to 64. >>most bioses initialize with 32. this had been a known problem, for me too. >>this has been left out of the discussion at via forums. >> >>and what knows a usb controller about MPEG? thats another layer. >> >>so a bios fixes this and other os have no problem with this, >>so its fixable by software. then do it now, pls. > > If you have such a fix, great, but while we don't have it, it is better > to blacklist pci2pci transfers (there are other supported methods that > are a little slow, but works as well as), than to offer a risk of mass > corruption at their disks. yes, indeed a good point. remember i blamed the v4l bt87x driver with xawtv for corrupting my root fs on kernel 2.4 some years ago, you can find the bug report on the v4l list, if i remember it right... > > Btw, are you sure that other OS offers pci2pci transfers for those > devices/chipsets? the question is *if* the hardware can handle this, as you said, so blacklisting hardware that cannot handle this error free should be ok, sorry. but if windos hadnt had support for this, i wouldnt have been able to use overlay video with the hauppauge wintv bt87x for years without any issue i can remember... right? > > >>and stop this "blacklisting habit", all these nowadays chips are >>designed-to-cost >>"consumer crap" somewhow. >>or do you want linux-usb to be blacklisted as "broken" by the manufacturers >>blacklists? ;) >> >> >>y >>tom >> > > Cheers, > Mauro. > > cheers, tom ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
