Hi Paul,

Am 10.01.19 um 20:56 schrieb Paul Burton:
> Hi Oleksij,
> 
> On Sat, Jan 05, 2019 at 05:39:06PM +0100, Oleksij Rempel wrote:
>> Hi all,
>>
>> I'm working on Atheros ar9331 related patches for upstream. Suddenly
>> this architecture is not working with latest mips_4.21 tag. Bisecting is
>> pointing to dma-mapping-4.20 merge.
>>
>> The symptoms are following:
>> - networking is broken, getting tx timouts from atheros network driver.
>> - depending on configuration boot will stall even before UART is enabled
>> - after reverting some of dma-mapping patches, network seems to work but
>> init will trigger segfault. It is running from nfs-root.
> 
> Could you please try with v5.0-rc1 & let us know how that goes?
> 
> The mips_4.21 tag was based upon v4.20-rc1 which had a bug in
> dma_alloc_coherent. That was fixed for v4.20-rc2 by commit d01501f85249
> ("MIPS: Fix `dma_alloc_coherent' returning a non-coherent allocation").
> 
> In general if you're planning to use the mips-next branch or a tag from
> it then I'd suggest always merging it with the latest -rc or the release
> of the appropriate kernel version, and possibly also the mips-fixes
> branch. Or just use linux-next instead of mips-next.
> 
>> First patch where regressions started is this:
>> commit dc3c05504d38849f77149cb962caeaedd1efa127
>> Author: Christoph Hellwig <hch@lst.de>
>> Date:   Fri Aug 24 10:28:18 2018 +0200
>>
>>     dma-mapping: remove dma_deconfigure
>>
>>     This goes through a lot of hooks just to call arch_teardown_dma_ops.
>>     Replace it with a direct call instead.
>>
>>     Signed-off-by: Christoph Hellwig <hch@lst.de>
>>     Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> 
> Having said that, I'm not sure the dma_alloc_coherent issue we had would
> have led to this patch being pinpointed by a bisect, so let's see.

With v5.0-rc1 dma issue is solved. To run v5.0-rc1 i need only two extra
patches:

SUNRPC: Fix TCP receive code on archs with flush_dcache_page()
and
Revert "mtd: add support for reading MTD devices via the nvmem API"

every thing seems to work fine... at least on Atheros AR9331.

-- 
Regards,
Oleksij