Memory resource problems with CardBus
proski at gnu.org
Sat May 15 14:29:03 EDT 2004
On Sat, 15 May 2004, Russell King wrote:
> On Sat, May 15, 2004 at 05:23:09PM -0400, Pavel Roskin wrote:
> > ef00c000-ef00cfff : 0000:00:0b.0
> > ef00c000-ef00cfff : yenta_socket
> > ef00d000-ef00efff : PCI CardBus #0a
> > ef00f000-ef010fff : PCI CardBus #0a
> > I don't see how an 8k (0x2000) size-aligned window can be allocated in
> > this configuration.
> You can, however, allocate two 4K resources successfully. However, one
> wonders why the bus is being allocated only 8K windows in the first place.
Indeed. If I reserve the region that the card uses by default
(reserve=0xef00d000,0x10000), the resources are moved elsewhere:
40000000-403fffff : PCI CardBus #0a
40400000-407fffff : PCI CardBus #0a
40400000-40401fff : 0000:0a:00.0
40400000-40401fff : prism54
Every window is 4 megabytes long! The prism54 card works now! The
details are here: http://www.red-bean.com/~proski/ak77/with-reserve/
> > It's interesting that lspci shows 4k long windows:
> > Memory window 0: ef00d000-ef00e000 (prefetchable)
> > Memory window 1: ef00f000-ef010000
> That's a lspci bug - it's reporting exactly what is in the registers
> rather than converting it into "reality". In reality, the windows
> for the above are:
> Memory window 0: ef00d000-ef00efff (prefetchable)
> Memory window 1: ef00f000-ef010fff
> since the lower 12 bits of the base _and_ limit registers are always
I'll report it after checking the latest version of lspci.
> Maybe we should get the kernel to automatically reallocate the windows
> if they're smaller than a parameterised limit defaulting to, say, 1MB ?
Sounds reasonable if the window sizes are set by BIOS. As I said, I have
no idea where those sizes come from.
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