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From: Bhuvan Kumar MITTAL <bhuvan.mittal@st.com>
To: <linux-kernel@vger.kernel.org>
Cc: <bhuvan.mittal@st.com>
Subject: How to make mmap'ed kernel buffer non-cacheable
Date: Fri, 20 Apr 2007 18:30:25 +0530
Message-ID: <000201c7834b$dda8c6c0$142ec70a@dlh.st.com>
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Hi,
  I am working on an audio device driver development on Linux. I have a kernel buffer which I have mapped to user space using mmap call from user space. My problem is that the data which comes to the kernel buffer is getting dropped in user space and I get only 50-60% of the data which is randomly ordered. The user to kernel level buffer address translation code is fine and I suspect this data dropping is occurring coz the kernel buffer is cacheable. Please suggest me some way of making the entire buffer non cacheable. I am stuck on this for quite a while now. 

Regards,

Bhuvan