iwlwifi problem with iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up intel_{alloc,free}_coherent()

iwlwifi problem with iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up intel_{alloc,free}_coherent()

[Fabio Coatti]

Hi all,
since kernel 4.17  my laptop fails to enable wireless card (04:00.0 Network 
controller: Intel Corporation Wireless 8260 (rev 3a) )
with this error:

Jul 01 09:34:36 hobbes kernel: iwlwifi: probe of 0000:04:00.0 failed with error 
-12

I bisected the issue to this result:
d657c5c73ca987214a6f9436e435b34fc60f332a is the first bad commit
commit d657c5c73ca987214a6f9436e435b34fc60f332a
Author: Christoph Hellwig <hch@lst.de>
Date:   Mon Mar 19 11:38:20 2018 +0100

    iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up 
intel_{alloc,free}_coherent()
    
    Use the dma_direct_*() helpers and clean up the code flow.
    
    Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
    Signed-off-by: Christoph Hellwig <hch@lst.de>
    Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: David Woodhouse <dwmw2@infradead.org>
    Cc: Joerg Roedel <joro@8bytes.org>
    Cc: Jon Mason <jdmason@kudzu.us>
    Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Muli Ben-Yehuda <mulix@mulix.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: iommu@lists.linux-foundation.org
    Link: http://lkml.kernel.org/r/20180319103826.12853-9-hch@lst.de
    Signed-off-by: Ingo Molnar <mingo@kernel.org>

:040000 040000 9b907b7d761c6121d603c649421749ffd4e13999 
2f396bd9e11c46e865a46107cd3cc9ef6f9ee6dd M      drivers


By reverting this commit the card works again, tested in 4.17.3 . I've noticed 
that the corresponding amd commit ( b468620f2a1dfdcfddfd6fa54367b8bcc1b51248)
has been reverted in linus tree (e16c4790de39dc861b749674c2a9319507f6f64f), 
and 4.16.X stable tree iirc,  but the intel one has not been reverted.

hw: Lenovo P50 Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz

Please let me know if more details are needed, but CC: me as I'm not currently 
subscribed to LKML.

many thanks.

Re: iwlwifi problem with iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up intel_{alloc,free}_coherent()

[Christoph Hellwig]

> By reverting this commit the card works again, tested in 4.17.3 . I've noticed 
> that the corresponding amd commit ( b468620f2a1dfdcfddfd6fa54367b8bcc1b51248)
> has been reverted in linus tree (e16c4790de39dc861b749674c2a9319507f6f64f), 
> and 4.16.X stable tree iirc,  but the intel one has not been reverted.
> 
> hw: Lenovo P50 Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz
> 
> Please let me know if more details are needed, but CC: me as I'm not currently 
> subscribed to LKML.

It probablty is the same issue.  Did you check if you can just revert
the commit cleanly on top of current mainline and that fixes the issue
for you?

Re: iwlwifi problem with iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up intel_{alloc,free}_coherent()

[Fabio Coatti]

On Monday 2 July 2018 15:19:51 CEST Christoph Hellwig wrote:
> > By reverting this commit the card works again, tested in 4.17.3 . I've
> > noticed that the corresponding amd commit (
> > b468620f2a1dfdcfddfd6fa54367b8bcc1b51248) has been reverted in linus tree
> > (e16c4790de39dc861b749674c2a9319507f6f64f), and 4.16.X stable tree iirc, 
> > but the intel one has not been reverted.
> > 
> > hw: Lenovo P50 Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz
> > 
> > Please let me know if more details are needed, but CC: me as I'm not
> > currently subscribed to LKML.
> 
> It probablty is the same issue.  Did you check if you can just revert
> the commit cleanly on top of current mainline and that fixes the issue
> for you?

Yep, it does. I issued a 
git revert d657c5c73ca987214a6f9436e435b34fc60f332a
on mainline (4.18-rc3) and recompiled, the card works just fine.

Re: iwlwifi problem with iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up intel_{alloc,free}_coherent()

[Christoph Hellwig]

On Mon, Jul 02, 2018 at 08:23:00PM +0200, Fabio Coatti wrote:
> Yep, it does. I issued a 
> git revert d657c5c73ca987214a6f9436e435b34fc60f332a
> on mainline (4.18-rc3) and recompiled, the card works just fine.

Thanks for confirming.  I'll end the revert to Linus this week.

Re: iwlwifi problem with iommu/intel-iommu: Enable CONFIG_DMA_DIRECT_OPS=y and clean up intel_{alloc,free}_coherent()

[Christoph Hellwig]

On Mon, Jul 23, 2018 at 02:28:16PM +0200, Fabio Coatti wrote:
> Hi, any hope to see this backported to 4.17.X as well? Just to avoid to
> revert that commit at every new release :)

You can send the patch to stable@.