From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 20 Apr 2004 09:45:55 +0800 From: llee Subject: Re: fail to disable MMU on ppc 8241 In-reply-to: <1082352050.1689.9.camel@gaston> To: Benjamin Herrenschmidt Cc: linuxppc-dev list Message-id: <408480D3.1030009@huawei.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed References: <40834DC0.2030408@huawei.com> <1082352050.1689.9.camel@gaston> Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Benjamin Herrenschmidt wrote: >On Mon, 2004-04-19 at 13:55, llee wrote: > > >>Hi, there, >>I boot linux (2.6.3) on my ppc 8241 through vxworks bootloader. I'd got >>a port (on address 0x70020006) to constrol three LEDs, so I could know >>where the kernel going. But after the disable_mmu is called, I lost >>control to the LEDs, Any suggestion on this? As I know, vxworks use a >>one-to-one mapping MMU setup, I should must constrol the LEDs through >>the same address. >> >> > >With mmu off, I suspect the 8241 acts as if the entire address space >was cacheable, which is a BAD THING for IOs typically. > >Ben. > > > > > > Thanks Ben, It works when I disable DATA CACHE! ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/