bt878 based dvr card vs. pci pass-thru

[Sipos Ferenc <frank@sudo.hu>]

Hi All,

I'm trying to set up a surveillance system in a domU using
pciback/pcifront to pass through the 4x bt878 chips, however this what I
get in the kernel logs:

"""
Dec 15 16:28:18 hive kernel: pciback 0000:07:0c.0: Driver tried to write
to a read-only configuration space field at offset 0x50, size 2. This
may be harmless, but if you have problems with your device:
Dec 15 16:28:18 hive kernel: 1) see permissive attribute in sysfs
Dec 15 16:28:18 hive kernel: 2) report problems to the xen-devel mailing
list along with details of your device obtained from lspci.
Dec 15 16:28:18 hive kernel: PCI: Enabling device 0000:07:0c.0 (0000 ->
0002)
Dec 15 16:28:18 hive kernel: ACPI: PCI Interrupt 0000:07:0c.0[A] -> GSI
16 (level, low) -> IRQ 16
"""
(Such message for every bttv chip.)

According to option 1) above here is what's in my
xend-pci-permissive.sxp file:
"""
(unconstrained_dev_ids
    ('0000:07:0c.0'
    '0000:07:0c.1'
    '0000:07:0d.0'
    '0000:07:0d.1'
    '0000:07:0e.0'
    '0000:07:0e.1'
    '0000:07:0f.0'
    '0000:07:0f.1')
)
"""

lspci says (relevant part only):
"""
0000:07:0c.0 Multimedia video controller: Brooktree Corporation Bt878
Video Capture (rev 11)
0000:07:0c.1 Multimedia controller: Brooktree Corporation Bt878 Audio
Capture (rev 11)
0000:07:0d.0 Multimedia video controller: Brooktree Corporation Bt878
Video Capture (rev 11)
0000:07:0d.1 Multimedia controller: Brooktree Corporation Bt878 Audio
Capture (rev 11)
0000:07:0e.0 Multimedia video controller: Brooktree Corporation Bt878
Video Capture (rev 11)
0000:07:0e.1 Multimedia controller: Brooktree Corporation Bt878 Audio
Capture (rev 11)
0000:07:0f.0 Multimedia video controller: Brooktree Corporation Bt878
Video Capture (rev 11)
0000:07:0f.1 Multimedia controller: Brooktree Corporation Bt878 Audio
Capture (rev 11)
"""

For some reason my system froze the other day (dom0) and I'm not sure if
this has anything to do with that as I was not able to gather any
information on what might have caused the freeze.

If anyone has any thoughts on how to make those warnings go away or has
experience with similar setup, please put me on the right track.

Thanks,
Frank

PS: Devguys, please note I'm not subscribed on the -devel list, so
either reply to me directly or the -users list which is also copied on
this mail.