Re: PCI: Cannot allocate resource region 0 of device 0000:00:0d.0

[Matthew Wilcox <willy-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org>]

On Sat, Apr 24, 2004 at 11:26:20PM +0000, trooper ryan wrote:
> Anyhow, the info you requested:
> # setpci -s 00:0d.0 BASE_ADDRESS_0=ffffffff
> setpci -s 00:0d.0 BASE_ADDRESS_0 returns 00d7f008 sometimes and ffffffff 
> others.

This is quite suspicious.  ffffffff would indicate this device is not
connected to the bus [1] .  The other value returned indicates it's a
32-bit BAR (entirely plausible) which is prefetchable (seems kosher for
a video capture card).  The base address would then be 0x00d7f000 which
is slightly under the 16MB boundary.  Very curious as this is normally
assigned to system RAM.

All in all, this looks like a pretty broken piece of hardware to me.
Possibly something else is going on to cause this, like the system being
over its power-budget.  I advide you to treat this as a hardware problem
and try doing some things to narrow it down, like taking all other cards
out of the machine and seeing if the problem persists; try the card in
a different slot; check the card connectors for damage, etc.

It'd also be worth trying a different OS with it, just to be sure it's
a hardware problem ;-)

[1] Due to how PCI BARs work, there must be at least one bit clear.
If it's a memory BAR, bit 0 must be clear, and if it's a port BAR, bit 1
must be 0.  If there's no reponse from a device, the PCI bus floats high,
so you get back 0xffffffff.  When you write 0xffffffff to a BAR, the device
ignores the bits that are less than the size of the aperture so when you
read it back, you should get only the implemented bits set.

-- 
"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain


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