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Date: Thu, 16 Jan 2003 09:51:43 +0530 (IST)
From: Madhavi <madhavis@sasken.com>
To: <linux-kernel@vger.kernel.org>
Subject: ioremap_nocache() behavior
Message-ID: <Pine.LNX.4.33.0301160942330.3848-100000@pcz-madhavis.sasken.com>
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Hi

I am testing the Device driver for a PCI network device on linux-2.4.19
and x86 platform.

I have noticed that the system hangs when I do a writel to a PCI MMIO
region. I tried ioremap_nocache() instead of ioremap() and the behavior
was unpredictable. It hung in a few cases and didn't hang in others. If I
did ioremap_nocache() just before calling writel(), writel seems to work
fine. I have checked the Base address in PCI configuration space using
"lspci -x" command and the driver is getting the correct values.

Any guesses why I am getting this problem? It would be very helpful for me
even if you can give a very vague idea.

One more question - How do I unmap the memory remapped using
ioremap_nocache()?

Thanks in advance.

Madhavi.

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