2015-07-10 19:36 GMT+08:00 Lars-Peter Clausen <lars@xxxxxxxxxx>:
> On 07/10/2015 01:32 PM, Lars-Peter Clausen wrote:
>>
>> On 07/10/2015 12:51 PM, Jun Nie wrote:
>>>
>>> Free descriptor when free chan resource as some device,
>>> such as soc soc-generic-dmaengine-pcm.c in audio side,
>>> may not release channel. This cause too much memory is
>>> cached for descriptor is not released.
>>>
>> [...]
>>>
>>> @@ -98,13 +98,10 @@ void vchan_dma_desc_free_list(struct virt_dma_chan
>>> *vc, struct list_head *head)
>>> while (!list_empty(head)) {
>>> struct virt_dma_desc *vd = list_first_entry(head,
>>> struct virt_dma_desc, node);
>>> - if (async_tx_test_ack(&vd->tx)) {
>>> - list_move_tail(&vd->node, &vc->desc_allocated);
>>> - } else {
>>> - dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
>>> - list_del(&vd->node);
>>> - vc->desc_free(vd);
>>> - }
>>> + list_move_tail(&vd->node, &vc->desc_allocated);
>>> + dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
>>> + list_del(&vd->node);
>>> + vc->desc_free(vd);
>>
>>
>> This is basically a revert of b9855f03d560 ("dmaengine: virt-dma: don't
>> always free descriptor upon completion"). Which was just introduced, so
>> this
>> is probably not what you want.
>>
>> Furthermore audio DMA uses cyclic DMA, so it doesn't even hit this code
>> path, so the patch description doesn't really add up to the changes.
>
>
> Sorry, it does. Looked at the wrong line. Reverting b9855f03d560 is probably
> the right thing to do as it breaks the existing semantics in a very bad way
> causing descriptors to be not freed when they should be.
I guess my change does not meet video requirement for patch
b9855f03d560, but I do not know detail video usage case related to
that patch. You can either revert the patch or confirm change in this
email is OK for the video case.
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