* Re: warning on device removal
[not found] <20080904122022.GA550@doriath.ww600.siemens.net>
@ 2008-09-04 12:36 ` Oliver Neukum
2008-09-05 6:56 ` Takashi Iwai
0 siblings, 1 reply; 2+ messages in thread
From: Oliver Neukum @ 2008-09-04 12:36 UTC (permalink / raw)
To: Dmitry Baryshkov; +Cc: linux-usb, linux-kernel
Am Donnerstag 04 September 2008 14:20:22 schrieb Dmitry Baryshkov:
> Hi,
>
> I've got the following trace on one of my arm boards when removing
> the usb masstorage device:
>
> ------------[ cut here ]------------
> WARNING: at /home/lumag/tosa-tree/arch/arm/mm/consistent.c:368 dma_free_coherent+0x34/0x248()
> Modules linked in:
> [<c0028fe4>] (dump_stack+0x0/0x14) from [<c003c810>] (warn_on_slowpath+0x4c/0x84)
> [<c003c7c4>] (warn_on_slowpath+0x0/0x84) from [<c0029e54>] (dma_free_coherent+0x34/0x248)
Looks like a principal problem we have with that architecture.
Is arm incapable of supporting buffer freeing in hard irq context
or do we use the wrong API?
Regards
Oliver
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: warning on device removal
2008-09-04 12:36 ` warning on device removal Oliver Neukum
@ 2008-09-05 6:56 ` Takashi Iwai
0 siblings, 0 replies; 2+ messages in thread
From: Takashi Iwai @ 2008-09-05 6:56 UTC (permalink / raw)
To: Oliver Neukum; +Cc: Dmitry Baryshkov, linux-usb, linux-kernel
At Thu, 4 Sep 2008 14:36:48 +0200,
Oliver Neukum wrote:
>
> Am Donnerstag 04 September 2008 14:20:22 schrieb Dmitry Baryshkov:
> > Hi,
> >
> > I've got the following trace on one of my arm boards when removing
> > the usb masstorage device:
> >
> > ------------[ cut here ]------------
> > WARNING: at /home/lumag/tosa-tree/arch/arm/mm/consistent.c:368 dma_free_coherent+0x34/0x248()
> > Modules linked in:
> > [<c0028fe4>] (dump_stack+0x0/0x14) from [<c003c810>] (warn_on_slowpath+0x4c/0x84)
> > [<c003c7c4>] (warn_on_slowpath+0x0/0x84) from [<c0029e54>] (dma_free_coherent+0x34/0x248)
>
> Looks like a principal problem we have with that architecture.
> Is arm incapable of supporting buffer freeing in hard irq context
> or do we use the wrong API?
According to DMA-API.txt, dma_free_coherent() must be called with IRQ
enabled:
> void
> dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
> dma_addr_t dma_handle)
...
> Note that unlike their sibling allocation calls, these routines
> may only be called with IRQs enabled.
Takashi
^ permalink raw reply [flat|nested] 2+ messages in thread
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2008-09-04 12:36 ` warning on device removal Oliver Neukum
2008-09-05 6:56 ` Takashi Iwai
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