Mauro Carvalho Chehab schrieb:
> Em Sat, 07 Nov 2009 15:05:02 +0100
> e9hack <e9hack@xxxxxxxxxxxxxx> escreveu:
>
>> Mauro Carvalho Chehab schrieb:
>>
>>> I agree. We need first to stop DMA activity, and then release the page tables.
>>>
>>> Could you please test if the enclosed patch fixes the issue?
>> Hi Mauro,
>>
>> your patch doesn't solve the problem, because saa7146_dma_free() doesn't stop a running
>> dma transfer of the saa7146.
>
> Well, it should be stopping it. The logic is to wait for an incoming dma
> transfer and then disable dma transfers:
>
> void saa7146_dma_free(struct saa7146_dev *dev,struct videobuf_queue *q,
> struct saa7146_buf *buf)
> {
> struct videobuf_dmabuf *dma=videobuf_to_dma(&buf->vb);
> DEB_EE(("dev:%p, buf:%p\n",dev,buf));
>
> BUG_ON(in_interrupt());
>
> videobuf_waiton(&buf->vb,0,0);
> videobuf_dma_unmap(q, dma);
> videobuf_dma_free(dma);
> buf->vb.state = VIDEOBUF_NEEDS_INIT;
> }
In my case, videobuf_queue_cancel() is called previously. videobuf_queue_cancel() wakes up
all buffers, but it doesn't handle the currently by the saa7146 used buffer. queue->curr
points to this buffer. Waiting for an incoming dma transfer in saa7146_dma_free() has no
effect for such a buffer.
Regards,
Hartmut
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