On 2014年08月16日 01:17, Mauro Carvalho Chehab wrote:
..........
>> +++ b/drivers/media/pci/pt3/pt3.c
..........
>> +static int pt3_fetch_thread(void *data)
>> +{
>> + struct pt3_adapter *adap = data;
>> +
>> +#define PT3_FETCH_DELAY (10 * 1000)
>> +#define PT3_INITIAL_DISCARD_BUFS 4
>> +
>> + pt3_init_dmabuf(adap);
>> + adap->num_discard = PT3_INITIAL_DISCARD_BUFS;
>> +
>> + dev_dbg(adap->dvb_adap.device,
>> + "PT3: [%s] started.\n", adap->thread->comm);
>> + while (!kthread_should_stop()) {
>> + pt3_proc_dma(adap);
>> + usleep_range(PT3_FETCH_DELAY, PT3_FETCH_DELAY + 2000);
>> + }
>> + dev_dbg(adap->dvb_adap.device,
>> + "PT3: [%s] exited.\n", adap->thread->comm);
>> + adap->thread = NULL;
>> + return 0;
>> +}
>
> Why do you need a thread here? Having a thread requires some special
> care, as you need to delete it before suspend, restore at resume
> (if active) and be sure that it was killed at device removal.
>
> I'm not seeing any of those things on this driver.
PT3 is a dumb device that lacks interrupt,
so the driver has to poll the DMA buffers regularly to know if
a DMA has finished.
I forgot to clean up the thread in remove() and will add it in the v2.
As with suspend/resume, I can add a check of freezing() like in
dvb_frontend.c::dvb_frontend_thread(), but if I remember right,
I had read before that someone pointed out that
the suspend/resume of DVB is not supported by DVB core,
and not many of other drivers seem to support it either,
so I thought I could omit this feature and rely on module re-probing.
Should I implement power management ops and set them to .driver.pm?
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