Messages in this thread |  | | | Date | Sat, 8 Dec 2001 10:39:25 +0200 (WET) | | From | Andris Pavenis <> | | Subject | Re: [PATCH] i810_audio fix for version 0.11 |
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Sorry, but this patch is still not OK. It still causes system locking up for me.
In some cases I have (I added printk in __start_dac): dmabuf->count = 0 dmabuf->ready = 1 dmabuf->enable = 1 PCM_ENABLE_OUTPUT set in dmabuf->triger
in __start_dac(). As result nothing was done in this procedure and I got system locking in __i810_update_lvi() immediatelly after that. This was reason why I added return code to __start_dac, __start_adc to skip the loop if there is nothing to wait for. Perhaps checking return code is more efficient and less error prone that repeating all conditions in __i810_update_lvi.
Maybe really we should use wait_event_interruptible() instead of plain loop in __i810_update_lvi(). This happens not so often, so I don't think it could cause too big delays. At least we could avoid kernel freezing in this way.
Andris
On Fri, 7 Dec 2001, Doug Ledford wrote:
> Doug Ledford wrote: > > > Well, unfortunately, neither of the patches you guys sent do what I > > was looking for ;-) My goal with that code was to enable a specific > > certain behaviour, and because of the deadlock I have to make a few > > changes elsewhere for it to work properly. The workaround patches are > > fine for now, but later today I'll make a 0.12 that fixes it the way > > I'm looking for. (Hint: it's legal for a program to call SETTRIGGER > > to disable PCM output, then call the write() routine to fill the > > buffer, then call SETTRIGGER again to start output, otherwise known as > > pre buffering, and I want to support that without forcing the DAC to > > be started on update_lvi()) > > > > The real answer is multipart: > > > > 1) during i810_open go back to the old behaviour of setting > > dmabuf->trigger to PCM_ENABLE_INPUT and/or OUTPUT based on file mode. > > > > 2) make sure that i810_mmap clears dmabuf->trigger > > > > 3) make sure that in both i810_write and i810_read, we force the > > trigger setting when we can't output/input any data because count <= 0 > > > > 4) in update_lvi make the check something like: > > > > if (!dmabuf->enable && dmabuf->trigger) { > > .... > > } > > > > That should solve the problem, I just haven't written it up yet. > > > > > > > OK, the attached patch should do what is mentioned above. > > Doug Ledford > >
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