From: Christoph Hellwig <hch@lst.de>
To: Oded Gabbay <oded.gabbay@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, Christoph Hellwig <hch@lst.de>
Subject: Re: Question about Power8/9, PHB3/4 and setting of DMA mask
Date: Wed, 3 Apr 2019 20:08:28 +0200 [thread overview]
Message-ID: <20190403180828.GC28682@lst.de> (raw)
In-Reply-To: <CAFCwf13rpx4HdWeW_Gw5NaaPnFB95z3qw5ATN=uDOMz2if_X5g@mail.gmail.com>
On Sun, Mar 31, 2019 at 12:50:21PM +0300, Oded Gabbay wrote:
> Due to some limitation in Goya, the driver first need to allocate a
> 2MB chunk in a DMA-able address under 39 bits and then we would like
> to move to using up to 48 bits. Therefore, the driver first tries to
> set the DMA mask to 39 bits, allocate the 2MB area and later on,
> change the DMA mask to 48 bits. On x86 this works fine.
You can't just change the DMA mask while you have active allocations,
this will fail for many implementations.
prev parent reply other threads:[~2019-04-03 18:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-31 9:50 Question about Power8/9, PHB3/4 and setting of DMA mask Oded Gabbay
2019-04-03 18:08 ` Christoph Hellwig [this message]
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