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

From: Konrad Rzeszutek Wilk
Date: Mon Dec 19 2016 - 09:33:19 EST


On Mon, Dec 19, 2016 at 02:57:00PM +0100, Geert Uytterhoeven wrote:
> 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?

Ah that does indeed work.

Which means I can't push it to Linus until rc2 at least.

Linus is sad when he sees git pulls that hadn't "soaked"
for two weeks in linux-next - and especially patches on top of
merges during the merge window.

>
> Please let me know what to do. Thanks!

Building and testing them now.

Wish there was some travis script to do this.