lkml.org 
[lkml]   [2018]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 06/10] swiotlb: use swiotlb_map_page in swiotlb_map_sg_attrs
On Mon, Oct 8, 2018 at 1:04 AM Christoph Hellwig <hch@lst.de> wrote:
>
> No need to duplicate the code - map_sg is equivalent to map_page
> for each page in the scatterlist.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> kernel/dma/swiotlb.c | 34 ++++++++++++----------------------
> 1 file changed, 12 insertions(+), 22 deletions(-)

Hey all,

So, I've found this patch seems to break userspace booting on the
HiKey960 board. Initially I thought this was an issue with the mali
drivers, and have worked w/ the mali team to try to find a solution,
but I've since found that booting just the upstream kernel (with no
graphics support) will see userland hang/block unless this patch is
reverted.

When I see the hangs, it seems like the filesystems are stuck or
something, as kernel messages still show up and sometimes I can get to
a shell, but commands that I run in that shell (like ls) just hang. I
don't see any other error messages.

Reverting this patch then gets it work. In order to cleanly revert the
patch, I have to revert the following set:
"arm64: use the generic swiotlb_dma_ops"
"swiotlb: add support for non-coherent DMA"
"swiotlb: don't dip into swiotlb pool for coherent allocations"
"swiotlb: refactor swiotlb_map_page"
"swiotlb: use swiotlb_map_page in swiotlb_map_sg_attrs"

But at that point if I just re-apply "swiotlb: use swiotlb_map_page in
swiotlb_map_sg_attrs", I reproduce the hangs.

Any suggestions for how to further debug what might be going wrong
would be appreciated!

thanks
-john

\
 
 \ /
  Last update: 2018-11-07 02:28    [W:0.284 / U:1.304 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site