| Date | Mon, 25 Oct 2010 09:12:51 -0700 (PDT) | From | Alex Dubov <> | Subject | Re: [PATCH 23/29] memstick: jmb38x_ms: use DMA for all TPCs with len greater that 8 by default |
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--- On Fri, 22/10/10, Maxim Levitsky <maximlevitsky@gmail.com> wrote:
> From: Maxim Levitsky <maximlevitsky@gmail.com> > Subject: [PATCH 23/29] memstick: jmb38x_ms: use DMA for all TPCs with len greater that 8 by default > To: "Alex Dubov" <oakad@yahoo.com> > Cc: "Andrew Morton" <akpm@linux-foundation.org>, "LKML" <linux-kernel@vger.kernel.org>, "Maxim Levitsky" <maximlevitsky@gmail.com> > Received: Friday, 22 October, 2010, 4:53 PM > This is to workaround a wierd > hardware bug: > > If PIO write is used, and then after it DMA write is used, > DMA > engine stops doing writes. > That condition even persists after device reset. > > To be maxumum safe, we do dma to a scratch page > and memcpy from/to it. > > Besides this change should just improve performance. > > Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com> > ---
I have not noticed this one before, and for all I know the driver was tested at Jmicron. Can you explain the issue a bit more?
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