Hello Christian,
Christian Ehrhardt wrote:
Hi,
I tried to use a radeon r200 based graphic card on a sequoia ppc
(440epx) board. I wondered about the initialization of radeonfb that
failed with
__ioremap(): phys addr 0x0 is RAM lr c029cf80
radeonfb (0000:00:0a.0): cannot map MMIO
radeonfb: probe of 0000:00:0a.0 failed with error -5
I trigger a check in ioremap, because the address it wants to remap is
0x0 which can never work. The reason of that is that the pci ressource
of that graphic card is not properly detected.
With some help I found two kernels - one that work and one that has
this issue.
Unfortunately they are very different:
good => 2.6.24.2 from the linux-2.6-denx - built for arch=ppc
bad => we have 2.6.25-rc9 (used in our kvm ppc project atm) - build
for arch=powerpc
I tried building the 2.6.25-rc9 with arch=ppc, but that one does not
boot so far. Because of that I can't surely tell you if it is only
that difference that breaks the pci detection.
We need arch=powerpc for our kvm code anyway, so I hope there is
another solution than to switch to arch=ppc ;-)
I came across a similar problem, which (ultimately) was caused by a lack
of memory reserved for PCI. I moved from 2.6.14(ppc) to 2.6.20(powerpc),
and suddenly some cards stopped working: the BAR registers were not
initialized, so it was not possible to access the cards.
Have a look at the boot-time messages, especially the early messages, as
the PCI subsystem is started very early in the boot process. You could
also try switching on PCI-debugging, and have a look at the debug
messages, or add some extra debugging info to the pci-initialization code.
Kind regards,
Johan
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-dev
