From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by oss.sgi.com (8.11.2/8.11.3) id f99KLAm22997 for linux-mips-outgoing; Tue, 9 Oct 2001 13:21:10 -0700 Received: from newsmtp2.atmel.com (newsmtp2.atmel.org [12.146.133.142]) by oss.sgi.com (8.11.2/8.11.3) with SMTP id f99KL5D22994 for ; Tue, 9 Oct 2001 13:21:05 -0700 Received: from hermes.sjo.atmel.com (newhermes [10.64.0.105]) by newsmtp2.atmel.com (8.9.3+Sun/8.9.1) with ESMTP id NAA27884 for ; Tue, 9 Oct 2001 13:12:20 -0700 (PDT) Received: from mmc.atmel.com (mail [10.127.240.34]) by hermes.sjo.atmel.com (8.9.1b+Sun/8.9.1) with ESMTP id NAA14640 for ; Tue, 9 Oct 2001 13:12:42 -0700 (PDT) Received: from mmc.atmel.com (IDENT:swang@pc-33.mmc.atmel.com [10.127.240.163]) by mmc.atmel.com (8.9.3/8.9.3) with ESMTP id QAA23468 for ; Tue, 9 Oct 2001 16:20:50 -0400 (EDT) Message-ID: <3BC36AE4.4D1EE63E@mmc.atmel.com> Date: Tue, 09 Oct 2001 16:23:49 -0500 From: Shuanglin Wang Reply-To: swang@mmc.atmel.com Organization: ATMEL MMC X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.2.17-8smp i686) X-Accept-Language: en MIME-Version: 1.0 To: linux-mips@oss.sgi.com Subject: MIPS and pci_alloc_consistent()? Content-Type: multipart/alternative; boundary="------------6F0868FCCD2EF1871F9797F2" Sender: owner-linux-mips@oss.sgi.com Precedence: bulk --------------6F0868FCCD2EF1871F9797F2 Content-Type: text/plain; charset=gb2312 Content-Transfer-Encoding: 7bit I tried to use the pci_alloc_consistent() to allocate one-page DMA'able memory for my device driver. But, when booting up the system, it was always failed to execute the pci_alloc_consistent() by showing some memory errors. I traced the code to the function __alloc_page() in the file mm/page_alloc.c, and found the system called "wakeup_kswapd()". But at that time, the kswapd process pointer is a NULL pointer and the wakeup-related codes don't check the pointer is NULL or not, so the system was stopped because of dereferencing the null pointer. I'm working on a MIPS SEAD-2 board using Linux kernel 2.4.3 MIPS distrinution. Anybody has some ideas about the problem? Or are there other convenient methods to allocate DMA'able memory? Thanks, -- Shuanglin Wang Atmel Multimedia & Communications 3800 Gateway Centre, Suite 311 Morrisville, NC 27560 --------------6F0868FCCD2EF1871F9797F2 Content-Type: text/html; charset=gb2312 Content-Transfer-Encoding: 7bit I tried to use the pci_alloc_consistent() to allocate one-page  DMA'able memory for my device driver.  But, when booting up the system, it was always  failed to execute the pci_alloc_consistent() by showing some memory errors.

I traced the code to the function __alloc_page() in the file mm/page_alloc.c, and found the system called  "wakeup_kswapd()".  But at that time,  the kswapd process pointer is a NULL pointer and the wakeup-related codes don't check the pointer is NULL or not,  so the system was stopped because of dereferencing the null pointer.

I'm working on a MIPS SEAD-2 board using Linux kernel 2.4.3 MIPS distrinution.
Anybody has some ideas about the problem?  Or are there other convenient methods to allocate DMA'able memory?

Thanks, 

-- 
Shuanglin Wang
Atmel Multimedia & Communications
3800 Gateway Centre, Suite 311
Morrisville, NC 27560
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