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From: Shuanglin Wang <swang@mmc.atmel.com>
To: linux-mips@oss.sgi.com
Subject: MIPS and pci_alloc_consistent()?
Date: Tue, 09 Oct 2001 16:23:49 -0500	[thread overview]
Message-ID: <3BC36AE4.4D1EE63E@mmc.atmel.com> (raw)

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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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             reply	other threads:[~2001-10-09 20:21 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-10-09 21:23 Shuanglin Wang [this message]
2001-10-10 11:38 ` MIPS and pci_alloc_consistent()? Ralf Baechle

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