* dma_pool broken on MIPS generic?
@ 2018-11-09 13:10 Alexandre Belloni
2018-11-09 13:24 ` Christoph Hellwig
0 siblings, 1 reply; 3+ messages in thread
From: Alexandre Belloni @ 2018-11-09 13:10 UTC (permalink / raw)
To: Paul Burton, Christoph Hellwig; +Cc: linux-mips
Hello,
I'm working on a (not yet upstreamed) dmaengine driver. While rebasing
from v4.19 to v4.20-rc1, I saw that it is not working properly anymore
because dma_pool is allocating descriptors in kseg0 which is cached
while in v4.19, it was allocating them in kseg1.
Am I missing something to explicitely state that the cache is not dma
coherent? How could I track this behaviour change?
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: dma_pool broken on MIPS generic?
2018-11-09 13:10 dma_pool broken on MIPS generic? Alexandre Belloni
@ 2018-11-09 13:24 ` Christoph Hellwig
2018-11-09 13:45 ` Alexandre Belloni
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2018-11-09 13:24 UTC (permalink / raw)
To: Alexandre Belloni; +Cc: Paul Burton, Christoph Hellwig, linux-mips
On Fri, Nov 09, 2018 at 02:10:14PM +0100, Alexandre Belloni wrote:
> Hello,
>
> I'm working on a (not yet upstreamed) dmaengine driver. While rebasing
> from v4.19 to v4.20-rc1, I saw that it is not working properly anymore
> because dma_pool is allocating descriptors in kseg0 which is cached
> while in v4.19, it was allocating them in kseg1.
>
> Am I missing something to explicitely state that the cache is not dma
> coherent? How could I track this behaviour change?
You probably want this commit:
https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git/commit/?h=mips-fixes&id=d01501f85249848a2497968d46dd46d5c6fe32e6
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: dma_pool broken on MIPS generic?
2018-11-09 13:24 ` Christoph Hellwig
@ 2018-11-09 13:45 ` Alexandre Belloni
0 siblings, 0 replies; 3+ messages in thread
From: Alexandre Belloni @ 2018-11-09 13:45 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: Paul Burton, linux-mips
On 09/11/2018 14:24:40+0100, Christoph Hellwig wrote:
> On Fri, Nov 09, 2018 at 02:10:14PM +0100, Alexandre Belloni wrote:
> > Hello,
> >
> > I'm working on a (not yet upstreamed) dmaengine driver. While rebasing
> > from v4.19 to v4.20-rc1, I saw that it is not working properly anymore
> > because dma_pool is allocating descriptors in kseg0 which is cached
> > while in v4.19, it was allocating them in kseg1.
> >
> > Am I missing something to explicitely state that the cache is not dma
> > coherent? How could I track this behaviour change?
>
> You probably want this commit:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git/commit/?h=mips-fixes&id=d01501f85249848a2497968d46dd46d5c6fe32e6
Yep, this helped, thanks a lot!
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
^ permalink raw reply [flat|nested] 3+ messages in thread
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2018-11-09 13:10 dma_pool broken on MIPS generic? Alexandre Belloni
2018-11-09 13:24 ` Christoph Hellwig
2018-11-09 13:45 ` Alexandre Belloni
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