Re: [PATCH v2 3/3] swiotlb: Add swiotlb=noforce debug option

From: Geert Uytterhoeven
Date: Mon Dec 19 2016 - 08:57:08 EST


Hi Konrad,

On Mon, Dec 19, 2016 at 2:38 PM, Konrad Rzeszutek Wilk
<konrad@xxxxxxxxxx> wrote:
> On Fri, Dec 16, 2016 at 02:28:42PM +0100, Geert Uytterhoeven wrote:
>> On architectures like arm64, swiotlb is tied intimately to the core
>> architecture DMA support. In addition, ZONE_DMA cannot be disabled.
>>
>> To aid debugging and catch devices not supporting DMA to memory outside
>> the 32-bit address space, add a kernel command line option
>> "swiotlb=noforce", which disables the use of bounce buffers.
>> If specified, trying to map memory that cannot be used with DMA will
>> fail, and a rate-limited warning will be printed.
>>
>> Note that io_tlb_nslabs is set to 1, which is the minimal supported
>> value.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>
> What is this based on? I can't apply it on my latest that I had
> sent to Linus?

I rebased it on last Friday's linux-next, due to the recent move of
kernel-parameters.txt.
All the rest should be identical to your linux-next branch.

> Could you rebase this one please on:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb.git stable/for-linus-4.9

That one indeed doesn't have the move of kernel-parameters.txt.

> Or if alternatively that does not - then please rebase it on
> b5cab0da75c292ffa0fbd68dd2c820066b2842de

However, my series already applies cleanly with git am on top of
that commit?

Please let me know what to do. Thanks!

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds