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From: "Imran Badr" <imran.badr@cavium.com>
To: "'lkml'" <linux-kernel@vger.kernel.org>
Subject: DMA from high memory regions
Date: Tue, 25 Jun 2002 16:29:58 -0700	[thread overview]
Message-ID: <002501c21ca0$3940ac40$9e10a8c0@IMRANPC> (raw)
In-Reply-To: <20020625230607.GA13960@netnation.com>

Hi,

I am trying to setup DMA to/from user space. I get a user pointer in my
device driver, from which I build up kiobuf and call map_user_kiobuf. After
this, I call kmap to map pages to kernel virtual space and then virt_to_bus
to get bus address. Now if I define CONFIG_HIGHMEM and that page happens to
be in the memory region near 1GB then DMA never happens and I donot see any
data in result pointer. If CONFIG_HIGHMEM is not defined, then everything
works perfectly. Please suggest any solution.

Thanks,
Imran.




  reply	other threads:[~2002-06-25 23:31 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-06-24 15:58 Linux 2.4.19-rc1 Marcelo Tosatti
2002-06-24 19:07 ` [PATCH 2.4.19-rc1] BLK_DEV_RAM not BLOCK_DEV_RAM. was: " Stelian Pop
2002-06-24 19:17   ` Rudmer van Dijk
2002-06-24 19:20 ` [PATCH 2.4.19-rc1] Fix building with 'make -r -R' Tom Rini
2002-06-24 20:28 ` Linux 2.4.19-rc1 Pawel Kot
2002-06-24 21:17 ` Linux 2.4.19-rc1 ChangeLog Summary Matthias Andree
2002-06-25 23:06 ` Linux 2.4.19-rc1 Simon Kirby
2002-06-25 23:29   ` Imran Badr [this message]
2002-06-26  0:23   ` Marcelo Tosatti
2002-06-28 22:41 ` bvermeul
2002-07-02 20:51   ` Marcelo Tosatti
2002-07-02 21:30     ` Marcelo Tosatti
2002-07-03 16:53     ` Bruce Harada
2002-07-12  0:26 ` Linux 2.4.19-rc1: [PATCH] tridentfb Helge Deller
     [not found] <7BFCE5F1EF28D64198522688F5449D5A03BFD8@xchangeserver2.storigen.com>
2002-06-26 16:43 ` DMA from high memory regions Imran Badr

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