Chris Wright wrote: > * Alexander Graf (ag...@suse.de) wrote: > >> Kenni Lund wrote: >> >>> 2010/3/31 Kenni Lund <ke...@kelu.dk>: >>> >>> >>>> Booting the guest and tuning to a DVB-T channel _works_ !!! :-D Thanks >>>> a lot for your help...I have one more question, though: If I have two >>>> devices (like the ivtv tuner and the USB card) and they share an IRQ, >>>> if I then assign BOTH of them to the same guest, will it then work? >>>> >>>> Alexander, the patch works, I hope to see it in a stable release in >>>> the near future ;) >>>> >>>> >>> Unfortunately, I have a correction to this :( It _almost_ works. I had >>> some video/audio artifacts which I though was caused by bad reception, >>> but after switching the DVB-T tuner back and forth between the PCI USB >>> card and a laptop, it got clear to me, that this was a passthrough >>> issue. I get no errors in dmesg on the host or in the guest. >>> >>> I recorded a short videoclip which illustrates the issue: >>> https://docs.google.com/leaf?id=0B-_nZameGeN-NDk4YzQ3N2EtMmEzMi00NTU4LWFjMjgtNzkxMzcxYzg2MTM1&hl=en >>> >>> >> Hrm, I'm not sure these would be related to the small BAR region patch. >> It looks more like a timing issue. >> > > small BAR == slow path == timing issue? >
Could be, yeah. The only chance I see to avoid that is to have in-kernel small BAR code that would issue the MMIO accesses without the userspace churn. One thing I could imagine would be < PAGE_SIZE memory slots. Then userspace just maps the 4K to the BAR, but passes only a part of it on as slot. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
