public inbox for linuxppc-dev@ozlabs.org 
 help / color / mirror / Atom feed
From: Johan Borkhuis <j.borkhuis@dutchspace•nl>
To: Christian Ehrhardt <ehrhardt@linux•vnet.ibm.com>
Cc: linuxppc-dev@ozlabs•org, Detlev Zundel <dzu@denx•de>,
	Hollis Blanchard <hollisb@us•ibm.com>
Subject: Re: pci issue - wrong detection of pci ressources
Date: Fri, 18 Apr 2008 16:23:16 +0200	[thread overview]
Message-ID: <4808AED4.7020507@dutchspace.nl> (raw)
In-Reply-To: <48088F02.2060806@linux.vnet.ibm.com>

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

  reply	other threads:[~2008-04-18 14:57 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-18 12:07 pci issue - wrong detection of pci ressources Christian Ehrhardt
2008-04-18 14:23 ` Johan Borkhuis [this message]
2008-04-18 16:29 ` Sergei Shtylyov
2008-04-19  0:48 ` Benjamin Herrenschmidt
2008-04-19  0:51   ` Benjamin Herrenschmidt
2008-04-20 20:36   ` Christian Ehrhardt
2008-04-20 21:36     ` Benjamin Herrenschmidt
2008-04-21 11:55       ` Christian Ehrhardt
2008-04-21 12:25         ` Sergei Shtylyov
2008-04-21 14:08           ` Christian Ehrhardt
2008-04-21 15:16             ` Sergei Shtylyov
2008-04-21 16:20               ` Sergei Shtylyov
2008-04-22 12:46                 ` Christian Ehrhardt
2008-04-22 13:31                   ` Sergei Shtylyov
2008-04-22 14:21                     ` Christian Ehrhardt
2008-04-22 14:27                       ` Michel Dänzer
2008-04-22 22:18                       ` Benjamin Herrenschmidt
2008-04-21 21:13         ` Benjamin Herrenschmidt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4808AED4.7020507@dutchspace.nl \
    --to=j.borkhuis@dutchspace$(echo .)nl \
    --cc=dzu@denx$(echo .)de \
    --cc=ehrhardt@linux$(echo .)vnet.ibm.com \
    --cc=hollisb@us$(echo .)ibm.com \
    --cc=linuxppc-dev@ozlabs$(echo .)org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox